Now I'm stumped, i cant find the info on the TBI's if they are a 2 bolt or 4 bolt main, ive looked everywhere and cant find the answer. Can someone please help me answer my question?

 

It depend was it out of a k2500 or something. What's the need for a four bolt ?

 

no its the original engine from my 89 camaro but i just want to know if its 2 bolt or 4 bolt before i pull it out for the rebuild i have to do to it

 

more than likely 2 bolt unless you have x-Ray eyes you need to pull the pan.

 

alright thanks!

 

I have a 350 1 pc RMS truck block.... 2 bolt mains. It just varies on a case by case basis.

 

Thanks guys, really appreciate the input, I really do!

 

Not even Vette L98's got a 4 bolt mains until the LT1 was introduced
As TP notes , on post '85 engines ,4 bolts are usually only found in the heavier trucks

The block style will have no bearing on your rebuild or parts required

 

^^^This^^^

I would add, it will have no bearing on the success of the project, the engine's durability, its longevity, or its output capability. It is exclusively for people who want to brag about having 4-bolt mains. The extra bolts are of no practical significance whatsoever in any manner way shape or form for what we do around here; all they do, is help out in situations where the engine is lugged at very low RPM for long periods of time. (think, pulling a trailer with a piece of heavy equipment on it, up a mud "road" on the side of a mountain, that takes a coupla hours to get all the way up) the factory's 4-bolt system is of no use against the stresses of high RPMs.

 

Wow, come to think about that it makes alot of since, thanks I've never thought about that ...when a 2 bolt pushes around a car that's light it doesn't need much for load, unlike a truck

 

Since you have a rod knock, If your not planning on stroking it I would look for another builder.

 

Its not even a rod nock, its spun and now the motor is seized

 

I agree with this point that 4-bolt factory mains are of zero significance here.
In fact, I have a hard time even believing they have any merit in the low rpm lugging example. I've seen hammered out rod bearings from this kind of use (detonation is what I believe it to be), but nothing to the main bearings and no evidence of cap movement on 2-bolt mains. The only time I saw evidence of cap walk on a 2-bolt main was on my buddy's 383 (balanced rotating assembly) spinning to 7100 and putting out 600+ hp. It's since gone back together with splayed 4-bolt caps.
I'm spinning my stock rotating assembly (not re-balanced) on the Impala to 7100, 540 NA hp, 660 on the spray and running the factory 2-bolt caps. 3 seasons of strip duty, and 1 season of roadrace/strip duty. All's good.
IMO, the factory 4-bolt arrangement is useless. Maybe some time in the past history of the SBC, there was merit in it to overcome some shortcoming that just doesn't exist anymore ??

 

Factory 4 bolt mains on a SBC are useless because there is not enough material at these locations in the block for the extra bolts to provide sufficient clamping force is a high-performance application... 2bolts mains are actually stronger..

Splayed 4 bolt mains on the other hand resolve that issue.

This can be done on a stock block, however the stock block does have other design flaws that can come back to haunt you depending on your application.

Depending on the application an aftermarket block may be the best answer.