97 C1500 383 Stroker build

[Erik the Awful]

My block was from a '91 Chevy K2500, 2 bolt main but I know a lot of people suggest that a 4 bolt main engine is a better foundation to build on. I am not sure how to identify the 4 bolt main engines.

If you're doing serious towing or getting near 500 hp you'll want 4-bolt mains. There's no way to tell without pulling the pan and looking at the main caps because 2 and 4 bolts are both machined from the same block casting. If you're going for all-out power, it's better to start with a 2 bolt main block and have it machined for splayed main caps, but I don't know how much a machine shop charges for that.

 

[L31MaxExpress]

4 bolt main is a better foundation to build on because the can take more power than the 2 bolt mains. If you wanna know if it's 2 bolt or 4 bolt you have to remove the oil pan and look at a crank bearing cap and count how many bolts are there. The pic below is a 4 bolt main if there was 2 instead of four then it's a 2 bolt.

2 bolt is a better foundation because you can put stronger splayed 4 bolt caps on them.

 

[best97obs]

true but if your adding any power adders such as turbo, supercharge, nitrous then 4 bolt is a better platform

 

[L31MaxExpress]

true but if your adding any power adders such as turbo, supercharge, nitrous then 4 bolt is a better platform

A factory 4 bolt is weaker than a splayed 2 bolt block. Then again if you are getting to the point of needing splayed caps, better to go with a Dart SHP block and go with a 4.125" bore. After running all the $$$ for my 383, I could have had a 415 for not all that much more.

 

[best97obs]

the crate motor I'm building is a splayed 2 bolt block so ill be fine.

 

[L31MaxExpress]

the crate motor I'm building is a splayed 2 bolt block so ill be fine.

My 383 would have been just fine as a 2-bolt but I happened to start with a 4 bolt block.

 

[best97obs]

oh dang man

 

[Night Bomber]

Just going to throw this out there to hopefully shed light on this from another angle.

I have a 1995 Chev K1500 that recently got an L05 and a 1998 C1500 that recently got an L31. Both were "massaged" and remanufactured by the same machine shop. The machine shop guys told me that both 4-bolt and 2-bolt blocks come from the same casting but the stronger engine blocks are the ones that came from factory with 2 bolt main bearings and have the additional bolts machined in afterwards by a caring machine shop. I'm more into driving my babies smoothly than I am into racing or abusing them so it didn't seem important to add this "upgrade" for all the difference it was going to make for me.