A friend of mine is purchasing an 89 GTA and it comes along with a 91 donor car that is supposed to have a 350TPI in it. My question is this, is the motor in the donor car a 2 bolt or 4 bolt main? I'm thinking about buying the engine and tranny from her to rebuild and if it has a 4 bolt main I will definately purchase it from her. Let me know, and thanks in advance!

 

If its the stock 350TPI it is a two bolt main.

 

Well that sucks. Would a Chevy Truck have a 4 bolt main of the same year? I have another friend that pulled a 350 TBI out of truck, like a 91 or 92 Silverado...

 

For just about anything you could run on the street it makes no difference whether it's a 2 bolt or 4 bolt main.

 

Yeah but even so, if I'm going to do it, I might as well get the strongest I can I figure. It isn't neccesary I know but it would be nice to have the extra strength.

 

Get a 2 bolt main and machine it for splayed caps then. Better yet, get an aftermarket block.

 

Yeah but at what cost for an aftermarket one? If I can get a used motor and tranny for $200 then why not!?! This way I have heads, intake, block, tranny, everything I need to rebuild what I already have under the hood, but without having to not be able to drive the car. Seems like a win win to me.

 

Then get the block and don't worry about whether it's 2 or 4 bolt.

 

I'm not exactly worried, was just curious as to whether or not it was 2 or 4. That was all.

 

The truck motors are a tossup. Usually the 3500 series trucks got the 4-bolt blocks; the light-duty trucks generally got the 2-bolts. Only way to really know is to flip it over and pull the pan.

 

Chevy/GMC 2500 trucks and Suburbans with 8-lug wheels had 4-bolt mains at least for the later ('87 and up) ones. I used to work at a place that sold rebuilt engines and trannies, and we used that as a guide for shops that hadn't pulled the pan yet or were just calling for a price quote. AFAIK, it was never wrong.

Works for ID'ing 4L80's if you have some dufus who doesn't know the difference and you're afraid he'll get the pan bolt count wrong -- 2500+ with 8-lug wheels has a 4L80 if it's an overdrive trannie.

Pat