This is a 1990-1991 L98 I bought for another project. Changed the oil pan gasket and noticed the pistons have very very shallow skirts compared to every other L98 or LT1 I've taken apart. I'll probably send my endoscope down a plug hole to see what the top looks like but, do these look stock?

 

That is from around the time GM was using Mahle pistons here and there in certain engines.

 

Interesting. My buddy said they look like Mahle pistons. So Mahle made stock cast pistons for GM during this period?

I'm more curious than anything. The oil pan has been off before, but the block has not been decked (engine suffix still there) so I'm not sure how far someone got into it. Found the oil filter adapter bolts interesting too.

Assuming it's stock, a 240hp engine with a 2200 stall converter in a 1200lb car should be fun.

-- Joe

 

I have no idea what pistons are in the picture.

In 1990 GM upgraded the pistons in the L98 engine in Y-body and F-body cars. They were Mahle. The were lighter and had a smaller dish that yielded a higher compression ratio.

I think it was 10.25 to 1 in aluminum headed Y-body cars and 9.7 to 1 in cast iron headed F-body cars.