2 Bolt or 4 Bolt Mains

Recently replaced the oil pan and also my oil pump. My engine has 2 bolt mains. I thought all Corvettes had 4 bolt mains.

Corvettes have never used a 4 bolt main engine exclusively. Most base/lo horse engines were of the 2 bolt variety...only the higher horse engines were 4 bolt, tho some low horse engines did get built with 4 bolt blocks if there was a shortage.

Joel is right.  The correct 010 block was available in either two or four bolt configuration, so you needn't worry.

Larry

I'll throw in a bit of trivia here...
The 4 bolt main small block wasn't even "born" until '68 or '69(I fergit), so even the high output fuelie('57-'65) engines were 2 bolt mains...
This only proves that you can build a hot rod engine with a 2 bolt block.

You are right.  I had forgotten that.  I had a 283 that made over 500 HP and turned 9,000 RPM.  It lasted for years of abuse.  I finally gave it to a friend in Vegas.  He built a sand rail around it and abused it for several more years before it finally went bang.

Larry

A lot of 400 ci in small blocks used in the roundy-rounds are 2 bolt mains and they are on the upper end of the RPM range for the whole race. My buddy has had the same 2 bolt block in his race car for over 10 years - rebuilt several times with different rotating assemblies and heads, but she's still turnin left!! LukesVette2009-10-24 07:34:28

MY BASE 300 ENGINE WAS BUILT WITH 4 BOLT MAINS.

There's no way of knowing what the main configuration is without looking at the mains. Casting numbers won't really tell the whole story. Sometimes, the stamped suffix numbers can point to a 4 bolt configuration, but not always.
On a 400(early, '70-'76 or so), it's a little easier...just look for three freeze plugs on the sides of the block. Three freeze plugs on a 400 block means it is 99.9% certain to have a 4 bolt main. Some 400 blocks only had 2 freeze plugs...those were almost always 2 bolt mains. All 400 blocks had three bosses for the freeze plugs, but on some of them, mostly the two bolt kind, the center boss was not machined for a freeze plug, so they only have two actual plugs in them, altho there were also some 2 plug blocks that has 4 bolt mains....confused yet?
Lots of earlier, "base"/ low HP engines did have 4 bolt mains, even into the mid '70s.
Adams' Apple2009-10-27 05:05:17