Sorry to break in, couldn't find it anywhere. I have a chance to buy one tommorrow.

Anyone know for sure L98 is it 2 bolt main or four bolt main? 1989 trans am

Thanks

 

I pretty sure it is a 2 bolt but i could be wrong

 

camaros and firebirds got 2bolt mains, corvette i believe got 4bolt. i kno for a fact that camaro and firebirds got 2 bolt mains.

 

Yep, 4 bolt mains were only in the vette cars

For what it's worth, unless you're going BIG!!!!!! - The 2 bolt will be just fine for whatever you wanna do. Even then, you can ADD the extra two if ya REALLY need 'em, and it'll be stronger than a stock 4 bolt main.

 

I have a 1990 L-98 vette shortblock in my car ....... Sorry guys but it is a 2 bolt main engine the 4 bolt vette thing is a myth, even my 82 vette with a L-83 CFI is a 2 bolt ....... Only difference I saw between a F-body L-98 and a vettes lower end is the vette has a different oil pan and pickup assembly and the vette also has a windage tray.

 

The most popular places you find the 4 bolt main "638" blocks is in trucks, or the ZZ4 crate motors. I guess GM's engineers figured the trucks need the extra strength of the 4 bolt caps more than any of the performance cars do. This holds true for the "010" casting 2-pc. RMS 350 blocks too. Most of the forged crank, 4 bolt ones came in the trucks.

 

I have to disagree. I pulled a L98 engine from a 1988 Trans Am GTA and by my suprise it was a 4 bolt block. Plus it was the original engine to that car according to the block serial number.

 

My 88 GTA had a 2 bolt L98

 

I totally believe ya dude. That's just the thing with GM when it comes to things like this. Some end up getting a 4 bolt block somehow, while the majority of them seem to get the 2 bolt. When you look at block casting #'s on mortec.com, a lot of them have a footnote saying it can be either 2 bolt or 4 bolt, so the only way to ever know for sure is to pull the oil pan and look for yourself.