How to tell the difference between a 2 bolt and 4 bolt main They didn't have any and the salesman said, "All the guys are using regular bolts of the same size. This information enables you to identify these blocks without removing the oil pan. Nov 1, 2011 · So ive been collecting parts to convert my 2v 351c into a 4v 351c. Jan 22, 2023 · It features 4. Jan 25, 2010 · For 350 roller tappet blocks look for casting numbers 10243880,14011148, 14088526, and 14093638 these can be a 2 or 4 bolt block. 25 cranks. 3L Power Stroke Diesel - Starter confusion: 2-hole vs 3-hole, long nose vs short nose - I'm confused by a starter for my 2003 F350 7. Thanks in advance for any replies. Dec 31, 2008 · The freeze plugs don't identify a 400 vs 350, if a 400 has only two freeze plugs on the side of the block it's a two bolt main, if there are three plugs on the 400, it's a four bolt main. What made it a 4 bolt was a machining process, not the core Jan 11, 2009 · I was asked," whats the difference between 2,4, and a splayed bolt block" on a normal chevy engine with 4 bolt main caps the caps look like this, notice the front cap is a two bolt main cap which is normal even on four bolt block where all the other caps have four bolts the better machine Feb 21, 2007 · Looking to buy a 350 v8 for my yj project. A 2-bolt is fine in most applications for further assurance, main studs can be used to give added strength and the mains can be steaked to help prevent cap walk. The L65 (250 hp 2 bbl) and LM1 (255 hp 4 bbl) 441 heads had 76 cc chambers for a 9. Oct 20, 2022 · What else can I help you with? How do you tell a 4 bolt main Chevy 350? The main bearing caps will have four ( 4 ) bolts instead of two ( 2 ) they will be side by side. Feb 2, 2015 · The main differences were heads, intake, and carb. Build it, enjoy it. All you have to do it LOOK AT IT!!!!!! Aug 8, 2024 · Compare the design, advantages, and disadvantages of 2 bolt and 4 bolt main bearings. May 29, 2023 · Deciding between a 2 bolt or 4 bolt main engine requires understanding their maintenance, upgrade, and repair costs. Dec 26, 2019 · For all out racing and high horsepower I would say you would want a 4 bolt main but there is even debate on a two bolt vs a four bolt main on strength wise. Discover when to choose each type for optimal engine performance and durability. Like the Gen V, all engines feature four-bolt mains. 1970, 1971 and 1972 400's are 4 bolt main blocks. Feb 3, 2018 · C3 Tech/Performance - 2-bolt or 4-bolt Mains? - Here's a photo of oil ports off my 454. Nov 13, 2007 · Just as the header says, on a 12 bolt 4. May 8, 2013 · Converting a 2 to a 4 bolt main block was pretty common back when these Blocks were hard to come by and the only Blocks avalable were GM. Buy a 2 bolt main, argrue its not a 4 bolt, and therefore not worth as much to you, use that as leverage to get the motor cheaper. Please chime in. I found a solid running 350 2 bolt for 350$ and cant decide whether to get Feb 12, 2007 · C3 Tech/Performance - 2 Bolt or 4 Bolt Main - Ok I am confused. Is there any away to tell the diffents from a 2 bolt from a 4 bolt. When I tore my engine down from my original 77, it is a blue 2-bolt main. And if they are 3/4 it is a four bolt motor. 25" diameter mains to accept the factory 4. Jun 21, 2003 · A good friend bought a '69 4-4-2 convertible back in the day with a dead 400, 4 speed and a 3. It is all in the machining. 2 bolt and 4 boltsmall block or big blocklong block or short block Jul 13, 2010 · how to tell if a 4 bolt main block has been converted from a 2 bolt main block. Discover their material properties, applications, and how to select the right bolt for your project. 72" exhausts. Is there a big strength difference between the 2 and 4 bolt versions? For my application would you recommend finding a 4 bolt main, or will a 2 bolt main hold up? Will be doing east coast wheeling. The 12530283 GM Goodwrench motor is for the 3/4 and 1 ton trucks only. Oct 16, 2001 · My question is regarding the difference between the 2-bolt block and the 4-bolt block. The blocks used with vortec heads the fuel pump boss is there but not drilled for a fuel pump push rod. You can get a used four bolt block for way cheaper than the four bolt conversion parts and labor charges. Bolts meeting SAE J429 standards have radial lines engraved on the bolt head. I know that a 4 bolt main block is stronger than the 2 bolt main blocks, but one of the books I was reading said that the 2 bolt main engines is fine for 350-400 HP, or something Oct 8, 2014 · Nope, many 2 & 4 bolt blocks use the same casting. The main caps are the caps that clamp down onto the crank shaft. The only way to tell if it is a 4 bolt is if you pull the pan. If your doing a motor swap its a simple change. Aug 27, 2008 · If you are shopping for a 4 bolt main, and dont plan on making huge power, I personally think you are wasting your money. Read 40 Years of 348 And 409 W Engines for more information. 56 Posi, how do you distinguish between a 3 series carrier and 4 series carrier with the cover off? I understand that it is more than likely a 4 series due to the gearing, but would like to validate 'more than likely'. This is a look at the two different small block Chevy rear main seal designs. As a crucial component within the heart of an engine, the 4-bolt main configuration plays a pivotal role in supporting the engine’s power and reliability. Feb 28, 2017 · The block is no different than any other one piece rear main seal roller block. The L82 had 2. May 21, 2014 · C3 General - 2 bolt or 4 bolt big block - So, I know they made 2 and 4 bolt version of the 396/427/454 blocks with the same casting numbers but is there any way short of pulling the pan to tell? I seem to remember reading in performance book put out by chevrolet that all early 4 bolt blocks were drilled and tapped for Jan 13, 2009 · I can pick up a complete 2 bolt 454 for $275 locally or I can pay $450-$500 for a 4 bolt main short block. Thank you! The L82 featured many different components than the L48. 00" stroke crankshaft. The motor look like it has either a Camaro a/c braket or Aug 16, 2019 · The base V8 engine is supposed to be a 2 bolt main. Discover why 4 bolt main engines outperform their 2 bolt counterparts in this comprehensive article. I know a Dec 10, 2011 · General Q & A - Help to identify block yr and 2 or 4 bolt - Casting # is 10114182 I know it is a 454 but I have seen some people say it is a 2 bolt and some say 4 bolt. A 1 piece will have a 3" bolt pattern and a 2 piece will have a 3. :streetrac Mar 9, 2014 · It's not worth it to take a factory two bolt and turn it into a 4 bolt unless you know someone who owns a machine shop and can do the work for free. Dec 30, 2009 · Vortec 880 block 2 or 4 bolt? How to tell?? Engine & Drivetrain Feb 19, 2005 · The casting number tells you only that this was the casting that they used for the 4 bolt main --- Not that it actually was machined for the 4 bolt caps. The easiest way to tell which rear main seal you have is by the year of the vehicle that the engine came from. The 880 is the Vortec block it appears in mid 1995 production with swirl port heads and TBI and may have a flat tappet cam but is fully provisioned for a roller in all instances. They do not sonic test very well bored more than that. The Chevy 350 4 bolt vs. 4 bolt mains were used on the optional high performance engines and some truck applications where the loads were more demanding. Jun 9, 2022 · The SAE J429 standard has specific requirements for bolts, screws, studs, sems, and U-bolts up to 1-1/2" in diameter. on splayed caps, 4 bolt mains etc. Nov 2, 2020 · This article will explain how to properly ID a GM differential carrier by examining your diff's ring and pinion gear set. 12", the valve cover bolts run into 2 of the ports causing a vacuum leak if you try to run with the cover off. Which is better, what are the pros and cons of both, how can I upgrade, what the heck is a main? Jun 30, 2008 · I looked up the number and most sites say it's either a 2 or 4 bolt main. I have a guy that has built sheet and all 2 bolt main machined and all with an eagle crank shaft cost him $800, Comp can shaft $280 it cost him performance pistons, rods n intake for $1100 because he needs the money had How to identify a 4 bolt main small block chevy. Can some one tell me what 2 bolt / 4 bolt refers to and why I want the 4 bolt main on my 396 SS. I never go more than . 421 block with 4-bolt 3. In this gui Jan 31, 2023 · 1999 - 2003 7. I am wondering if anyone knew for sure. I can tell the engine has been rebuilt before because of You can either locate some mains from an otherwise scrap 4-bolt block or convert a 2- to 4-bolt mains by using aftermarket steel caps. These are with a 4-bolt engine block for durability. You can look at the crank flange at the flywheel. I've decided that I want a 427 over the other engines. Jan 19, 2016 · The strength difference between a 2-bolt and traditional 4-bolt is not that significant as you remove much metal to make room for the extra bolts. 56's. Jun 10, 2002 · All times are GMT -4. the 2 bolt man is a hot topic. Unless you are building a pumped up motor, 2 bolt mains have been used very reliably for many many years. The code K truck is considered a heavier duty option than code C trucks which improves the likelihood of the block having 4 mains, a manual transmission in the truck almost guarantees it's a 4 bolt. Not sure what the means. Accessories, such as bases and rings, magazines, etc. Some say there for 1 piece rear main seal and others say there for 2 mains. Nov 4, 2004 · Get notified of new replies To 4 bolt main vs 2 bolt main Subscribe Reply Subscribe Tags Jan 16, 2005 · Chevy girl, 2, or 4 bolt main, refers to the number of bolts holding the crankshaft main bearing caps in place. Although the cam is stronger in the L82, it’s physically identical to the L48. I this is the easiest way to tell if you have a 2 bolt or 4 bolt main #viral #chevrolet #diy Nov 17, 2008 · Hello guys sorry for the posts but what are the differences between the one piece seal and two piece seal 350 blocks? I know the difference in the rear main seals thus the difference in terminology but what about the bolt on stuff? Basically what I want to know will any small block chevy heads Hello! Engine in question is a '70 350/300HP out of a Kingswood station wagon. If strength is important, ensure that both the grade and manufacturer identification markings are present. It will be stock and running on propane. Jan 23, 2020 · Milodon’s aftermarket four-bolt main caps with angled (splayed) side bolts provide the extra strength needed for a big-horsepower build. You will probly spin a rod bearing before you crankwalk though so it doesnt matter. The 4 bolts hold up to more abuse than a 2 bolt set up. - The above applies to original unmolested 350's and has checked out in my experience. Aug 30, 2003 · All 400 Chevrolets are siamesed. The original A-Bolt and the A-Bolt II. 3 - Here is some background about why I'm confused. 6l engine??Any help would be appreciated. Jun 14, 2010 · - The font size of the block casting number (3970010) comes in two sizes. Ford’s objective with the 335 block was strength with thicker decks and main webs. He states that if the plugs above the oil filter are 5/8 inch it is two bolt. 3/4 ton up are 4 bolt mains, 1/2 tons are 2 bolt. The block casting number is 3999289 with casting date of F14-73. Example, one of the most popular quoted block casting numbers is 3970010, it was a 2 OR 4 bolt block depending on what it was to be installed in. Sep 5, 2001 · C3 Tech/Performance - 2 Bolt or 4 Bolt mains, does it really matter? - For a street car that is. The engine had been upgraded to a 350, and while we were discussing his car/engine, the owner asked me if I could tell if it was a 2bolt or Customer: have a chevy 350 engine #3970010 how can i tell if it is a 2 bolt or 4 bolt main Oct 18, 2021 · A 2-bolt main with aftermarket studs is stronger than a 4-bolt main block, less prone to crack, and can take up to 600 HP on a seasoned block. 94 inches. The oiling system, which gets a lot of criticism, was a cost issue more than anything to reduce the number of machining steps. 1967 Chevelle, SS Clone, 396, 4 speed, 12 bolt posi Centennial, CO Aug 16, 2011 · how to tell the difference in a 351c 4 bolt main. . I tow with it, and use it for typical truck stuff. I believe the 2-bolt block casting numbers are in a larger font than the casting numbers on 4-bolt blocks. I studded the mains and I have had no problems with it. Also wondering if there is any way at all to tell if heads are oval or square port by looking at them Sep 13, 2005 · I am looking into purchasing a date matched 396 for my 1966 Chevelle SS and was wondering if the 396 360 HP engine is a 2 bolt main or a 4 bolt main? I know there are two blocks for a 66 396, 961 and 962 but I am not sure which one is the 4 bolt main or maybe both are. In terms of outright strength, aftermarket angle bolt caps are the best option because they enhance block integrity. Jun 22, 2012 · What horsepower range would you reccomend going with a 4 bolt block over a 2 bolt block or is there even a divide? Sep 25, 2006 · well i bought this chevelle that is all original and the engine code is cnn which is 350 250 hp 2 barrel with th-350. Either way, they’ll need fitting and line boring. I wish the 1/2 ton trucks came with a 4-bolt main Jan 5, 2008 · Heads are otherwise the same, casting # D0OZ-6049-H with 2. Jan 28, 2010 · C3 Tech/Performance - 2bolt/4bolt Main Engine Identification - I was at an auto shop recently where the owner of a 57 chevy was having a front end alignment performed on his car. Give me some opinions - how much does 4 bolt buy you in reference to strength, performance and longevity? Thanks, Bill Dec 21, 2023 · A 2-bolt cap begets a 2-bolt main engine, while its counterpart, the 4-bolt cap, engineers the robust foundation of a 4-bolt main engine. Camaro, runs 11. Jul 28, 2005 · Now a 2 bolt main is obviously going to weaker than a 4 bolt at higher RPM/HP levels. All 421 blocks without exception were factory equipped with 4-bolt main caps. how to tell if its a Cobra-Jet or Ho block. Also, did the 360 HP Oct 22, 2022 · The primary difference between a two-bolt and a four-bolt 350 refers to the engine block's design, specifically the number of main bearing bolts used to secure the crankshaft. 25-1 CR. Both are very similar rifles and are considered part of a design family. The theory is t e wider the Chryslers withstanding 650 plus HP. If the oil pan is removed, you can see the bearing caps, otherwise an engine number, or possibly a Jun 16, 2012 · C3 Tech/Performance - What are the major advantages in a 4 bolt vs 2 bot main - Is the 4 bolt main really necessary or worth the extra $ in a soley used street car application? Dec 2, 2002 · If there an easy way to tell if a 350 is a 4-bolt main without pulling the oil pan? Do casting numbers tell this? It is in a 75 blazer with a 465/205 Jun 16, 2012 · C3 Tech/Performance - What are the major advantages in a 4 bolt vs 2 bot main - Is the 4 bolt main really necessary or worth the extra $ in a soley used street car application? Dec 2, 2002 · If there an easy way to tell if a 350 is a 4-bolt main without pulling the oil pan? Do casting numbers tell this? It is in a 75 blazer with a 465/205 Apr 17, 2007 · I'm just starting to learn about engines and hoping to get a68-72 El Camino soon, so I have been reading up on them. What usually fails first a rod or a main? Thanx Cory Oct 6, 2005 · General Q & A - 2 bolt main vs a 4 bolt main - I am rebulding an older Scarab 30- I bought it with a blown engine (a two bolt main). 2-Bolt vs. Aug 31, 2007 · Most times there is no way to tell untill you pull the pan, there are a very few casting #s that are only 4 bolts but I can't tell you what they are. The above identifiers are correct, the larger, relieved harmonic balancer, and the steam holes are giveaways. 4-Bolt Engine Block onnecting rods and pistons, primary engine RP ways has been the rule to go use of the engine. 2 is usually enough. I would not dwell much on the 2 vs 4 bolt thing unless you are doing some crazy high hp build or abusing it. Apr 11, 2008 · Depending on how hard it was expected to be used it came in 2 or 4 bolt main verities. I figure I can save the money on the block and throw it into the rods, crank, etc. Specs: 350/350/205 d60/14bolt and 42's. vortec headed or not. May 2, 2012 · 4 bolt main?010 has nothing to do with the main cap configuration, it is the core identification number for the side of a SBC. I prefer the 1 piece myself just because of less leakage. I'm building a weekend cruiser but would like it to have decent power. Aug 11, 2005 · 4 bolt=forged crank and extra sense of security that four bolts hold it instead of 2. 90 "12 Bolt". I think the V and VI's water pumps are different but what else and what will still interchange? Is the bell housing bolt pattern still the same? Also how many of the V and VI's cam Jan 30, 2004 · The 1st and 5th main cap have 2-bolts to hold the crankshaft in, even in a 4-bolt engine (unless modified from stock). but is the same casting as any '87 up one piece seal roller cam ready block 350 Mark Banned Jan 31, 2023 · The older 2 bolt main 350’s are as durable as the 4 bolt Main because of the since they aren’t splayed. Four bolt means there are four, which means more clamping force, and less likelyhood that the crank is going to push itself out of the bottom of the engine at high RPM / power. Feb 25, 2024 · i wanted to ask if anyone knows what the difference between the 3 bolt and 4 bolt steering gears are. How to identify a 1 or 2-piece rear main in an SBC. Each was designed for use with a limited range of ring-and-pinion gears. Apr 2, 2007 · Two bolt means each main cap uses two bolts to hold it down. made for the original A-Bolt and A-Bolt II will not fit the AB3. Mild motor 450 -500hp, 3000 lb. Two basic 351C blocks (two-bolt and four-bolt main) were produced with a variety of casting numbers visible above the starter. Nov 17, 2011 · the bolts you speak of are the main bearing caps on the crank. But now with the advent of after market blocks all this has changed. Jul 13, 2010 · how to tell if a 4 bolt main block has been converted from a 2 bolt main block. e. Bolts and screws also bear a mark to identify the manufacturer. Dec 3, 2007 · Difference Between 2 and 4 Bolt Mains Engine & Drivetrain Oct 29, 2005 · I'v got a 2 bolt main out of my 70 Lemans, I have read mixed reviews wether to spend the money on it or look for a 4 bolt to replace it with. The L48 possessed a cast crank, two-bolt mains and a cast-iron intake manifold AFT Technical Resources. He says it is supposed to be a 4-bolt from the factory. Selecting the appropriate bolt strength is a crucial decision in many engineering, construction, and manufacturing projects. 86" x 2. I read in this thread FTE Jan 18, 2002 · Re: 2 bolt main 4 bolt main? What's this mean? (Yellow75) The "mains" are where the crankshaft is held and it rotates on. Do not fall into the “4-bolt main” marketing trap. If I remember right some big blocks had plugs in them for external oil coolers and had HI PERF on the block, some 2 bolts had the Hi PERF also though. Lots of folks say that the 2 bolts are stronger but I have NEVER had a problem with the 4 bolt blocks either. is it possible to conver 351C-2V to 351C-4V? Do they use the same block? Thx Is a 454 a 4 bolt main? 454ci/L29: Rated at 290 hp, The Vortec 7400 is the last generation 454, with the same 4. thanks. Under most real world conditions a 2 bolt block is fine for most applications . A two bolt main block will have only two. There are also a police car head, D2OZ, with the same ports and valves as the CJ but bigger chambers. 02-inch valves and the L48 measures 1. is there a way to tell without taking off the pan? casting number is 14015445. if it originally was in a tow truck or some other heavy duty applicaiton? Let me know the myths of 2 bolt versus 4 bolt mains. Is it likely my Tahoe has the 4-bolt block? Click to expand If it is the stock engine that came with the truck, then no it is the 2-bolt main. Bolts are responsible for holding together everything from buildings to machinery, and choosing the wrong strength can lead to structural failures, safety hazards, and costly repairs. Learn how to identify the 4 main engine and what it means for you. I believe most all have a 8" balancer, not a 7", excluding a possible aftermarket replacement. Because there are so many different grades and fasteners all look about the same, medium carbon and alloy steel strength grades are marked for identification. Thanks guys. Dec 31, 2014 · rebuilding my 454 bracket motor, need a new block, finding a some 2 bolt blocks out there, old motor was a 4 bolt. No water between the cylinders on the middle bores. Jan 31, 2006 · I was told that some LT1 cars have 2-bolt mains while others have 4-bolt mains. If i understand it right, the 2-bolt was only in 91, and the 4-bolt was 92 and up. A chart to identify bolt grades using bolt grade markings; also provides a strength chart for common grade bolts. Aug 13, 2007 · In 1986 chevy changed the 2 piece rear main seal to a 1 piece rear seal, The 2 piece was notoriously famous for oil leaks. Apr 13, 2018 · When looking at a swap meet or salvage yard rearend, keep in mind that GM made three “types” of 12-bolt carriers (Type 2, Type 3, and Type 4). 5" bolt pattern. 030 on overbore. All in all, if you aren't going to be going over 400hp, a 2 bolt will suit you fine. 4 bolt for big blocks - like the 427 I am building not a stroked out 572 or anything. Steel cranks, forged pistons, larger harmonic dampers and other such heavy duty parts were usually specified along with 4 bolt mains. But you can always convert the 2 bolt main block to a 4 bolt main, but it would be cheaper in the long run to just find a good 4 bolt. Chevy Engine terms for beginners. 2 bolt and 4 boltsmall block or big blocklong block or short block Dec 8, 2009 · What is the difference between the 6 bolt and 8 bolt flywheel 4. Any Cleveland two-bolt main block can be converted to a four-bolt main if you have the stock iron or aftermarket steel billet caps. Apr 24, 2007 · C4 Tech/Performance - 96 LT1 is it a 4 bolt main or 2 bolt - I am look at purchasing a 1996 LT1 motor and the guy does not what to take the oil pan off to verify if its a 2 or 4 bolt main. Dec 25, 2008 · A four bolt main block will have four bolts that secure the main bearing caps to the block. Thanks. Apr 1, 2009 · Hi the question is: what are the differences between 1971~1973 351C-2V engine and 1971~1973 351C-4V engine except intake manifold and carburetor. main cap base a Apr 19, 2015 · The somewhat peculiar-looking oil baffle/windage tray and dipstick tube arrangement that attaches to the #4 & #5 main caps is a feature specific to '64 and earlier blocks. All three of these designs are Feb 14, 2007 · Re: 2 bolt main vs 4 bolt main Most are 2 bolt mains, even the new Merc and Volvo MPI 5. Sep 17, 2014 · The A-Bolt was built in two main series. All input is appreciated. I've don't a bit of research and get conflicting results. I'm seriously ready to buy a rebuilt 427, I'm looking at one presently. Jan 23, 2006 · The 2 bolt or 4 bolt main is refering to the number of bolts holding the main caps for the crank inside the motor. You won't gain anything using 4 bolt mains unless you run 8 or 9,000 rpm all the time. The best method for determining 2 or 4 bolt main caps is to drop the pan and LOOK . The time now is 11:09 AM. Feb 25, 2008 · Can someone please explain or point me to a site that will tell what the differences are betwen these motors. I have built quite a few 400's (for myself and others). if necessary if I go with the 2 bolt main set up. He was going to drop the 400 Pontiac his brother had pulled out of his bracket car in it with a set of 4. I am getting confliciting information whether a 69 350 corvette block was a two or four bolt main. 0-1 CR and the L48 (300 hp 4 bbl) had 186 or 041 heads with 63 cc chambers for a 10. Any way I can tell if it's a 4 bolt main without pulling the pan? Thank Mar 12, 1999 · I just read that article on 12 bolts, If you look at the 3 carriers's they are backwards. Jun 23, 2006 · I am a mechanical novice when it comes to engines. If the hole is small, it's a 2 bolt and if it's large, then it's a 4 bolt. This seemingly minute divergence in bolt configuration wields profound implications for the engine’s structural fortitude and resilience. 00, 12:1, mild cam, old school simple. The 4 seires is the shortest because the pinon on a 4 seires is smaller in diameter and that makes the ring gear closer to the center line of the carrier. The L82 had larger heads and valves, four-bolt mains, forged steel crank, different pistons and aluminum intake. Do I need to stick with 4 bolt main? Just asking for some opinions. Jun 13, 2006 · I know in general 4 bolts are stronger than 2 bolt mains, but in an engine like this, wouldn't a 2 bolt main engine be expected to hold up, i. Some blocks use 2-bolts on the main caps, some use 4. The only thing that I'm not sure about is the fact that it's a 2 bolt main block. 4 is stronger. 5×4-inch bore and stroke as before. Most of the engine builders online, including some big brands, will drill extra holes on their 2-bolt main blocks and it makes the mains weaker and more prone to cracking. Is there a big enough difference in the 2 and 4 bolt to buy a 92 over a 91 3/S? I am asking because I am looking to buy Aug 17, 2018 · The Gen 2 LT1's most significant update over the Gen I small-block was a reverse-flow cooling system, which cooled the cylinder heads first to achieve lower cylinder temperatures. 2 bolt main engines are cheaper to maintain, but 4 bolt main engines provide better stability and durability. Apr 6, 2002 · The 3 center main bearing caps have 2 bolts on each side in a 4 bolt main motor , holds the crank in check under high horsepower and high torque . Apr 1, 2024 · 2 Bolt vs 4 Bolt Chevy #automobile #engine #techtips Speedway Motors 89. I am running a 2 bolt 454. Partly, I would want to choose based on how rigid the shoe's sole is: a more-rigid sole makes a 2-bolt more practical since a 3-bolt adds rigidity with the bigger platform/contact surface on most road pedals (this isn't always the case). They had Grade 8, Grade 5 and Steel bolts, according to Dec 18, 2024 · Learn about the different grades of bolts, including Grade 2, Grade 5, Grade 8, and high-strength alloy bolts. Intake ports are ovals 2. Mar 6, 2009 · I found a BBC 454 and the casting number wont tell me if it 4 or 2 bolt main. I have been told I should thinking about converting it to a 4 bolt main. Here, we'll offer more details on different grades of bolts and their applications to help you find the best-suited grade for your projects. " So, I went over to the fastener section. Make sure that if you are going to convert to a 4-bolt you go with splayed main caps as the splayed bolts are exponentially stronger then the traditional bolts. I do not know how to tell without dropping the pan. s Jul 14, 2019 · I pulled a 454 out of a square suburban with a 4 bolt main (original block). The new AB3 — sometimes also referred to as an A-Bolt — is a different model and design. All 3 used the same flat top pistons, same cam, etc. Having the extra studs and bolts left from the ARP BBC stud kit and all the other mains converted to 4 bolt Caps, I desided to convert the 2 bolt rear cap t Jun 14, 2007 · Hey, We were arguing today about the effects of going 2 bolt vs. Jul 20, 2006 · C4 Tech/Performance - 4 bolt vs 2 bolt main - At what HP point should you worry about having a 4-bolt main on a 350 small block, with all internals being forged? Mar 8, 2011 · The Following User Says Thank You to luzl78 For This Useful Post: Jun 25, 2004 · I was looking at 4. I’ve built many of both with rpm range to 7,000 rpm. However how in the world can i tell if its a 2 bolt or a 4 bolt not really sure what i am looking for. I am being told that pretty much all the older 70-79 454 330 horse were 2 bolt main blocks. 81-inch bore centers, two-bolt mains, and side oiling. They work with standard main bolts (left) or upgraded main studs (right) for even more power-holding capability. Feb 12, 2018 · The VIN on this Tahoe has the "R" as the 8th digit. This deals with one trick that I use that has always worked for me in identifying a 4 bolt main small block. Today Professor Clint takes on the topic of 2 Bolt vs 4 Bolt mains. But the only way to know for sure is to drop the pan and look. The 4 bolt main engines are generally considered more desireable, and stronger. It should be a forged one with the thick (wide) parting line at the OD, not a narrow parting line, which indicates a cast crank. my question was i can i tell without taking the oil pan off it is a 2 bolt or 4 bolt main. in this video I show you the quickest way to tell if your vehicle's engine has a 2 bolt main or 4 bolt main Without removing the engine or pulling the numbers Sometimes you can't get a block with 4 bolt mains though, so a way to make a 2 bolt main block even stronger than a typical 4 bolt block is to use a "main support". May 6, 2006 · C3 General - Is my '77 supposed to be 4-bolt or 2-bolt? - Had an interesting discussion with a potential engine builder yesterday. Apr 25, 2001 · I stopped at my local TSC to buy some 1/2 x 3" Grade 2 shear bolts for my Brush Bull rotary mower. Is there any way to tell with out actually pulling the oil pan? ie SS's and WS6 came with 4-bolt main. My question is this, for a guy on a budget, building a decent motor that sees the drag strip a few times per year, is it really worth the extra? Splayed caps can run into some serious money and if you are building a 350-450 hp motor, with Dec 10, 2011 · Hey guys I was wondering what's the big difference between a 2/4 bolt main. When they made it into a 1 piece the rear flange was made completely round and a smaller bolt pattern was used, so the flywheel/flexplate from a older 2 piece block will not fit on a 1 piece and vice versa. What Is A 4 Bolt Main? In the realm of automotive engineering, the term “4-bolt main” often surfaces in discussions about engine strength and durability. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Someone once told me that you could tell the difference between a 2 or 4 bolt main by looking at the size of a hole on the side of the block. Grade 2, 5, and 8 are the most common grades of fasteners according to the Society of Automotive Engineers standard. 24" intakes and 1. The plugs at the oil filter area are larger Jan 28, 2010 · A friend and I are having a different about being able to tell if a big block Chevy is a 2 or 4 bolt main without taking off the oil pan. Oct 4, 2010 · I am just wondering if the 4 bolt main deal is really worth it? I mean I have read all the magazine articles, books etc. 4K subscribers Subscribe Jun 24, 2010 · A 1 piece rear main and 2 piece rear main have different flywheels as well. I have a 1968 427 sitting on a stand all together and thought it was a four bolt main. Learn the advantages, key differences, and expert insights. 7's pushing 320 HP are only 2 bolt.