I have a 1977 cutlass supreme brougham I want to restore, it has the 350 rocket in it. Going to send the engine away to be rebuilt to get 400 ponies out of her. The only thing I want to know is the block one of the better blocks cause of after 76 they were thinner. The car was built in late summer of 76 and the air breather lid has 350 rocket on it. Is this the thicker block, or how to find out?

 

The block number is cast into the shelf behind the water pump. That will tell you what block you have. You can also look at the left cylinder head in front of the #1 spark plug for a large cast in number. If it's the later block it will have a large 3A. If you happen to have the early block (which I kinda doubt) it will be 8.

 

Okay, thanks alot

 

I looked, it has 3 A stamped. The car I bought for parts has an 8 stamped on it. So which one is worth the rebuild?

 

It sounds like those are the casting marks on the cylinder heads. You need to get the casting number of the block, which is located above the water pump, by the oil fill tube. I can almost guarantee that this will have casting no. 557752, which is a thinwall, windowed main web block. The older blocks have solid main webs.