I have been researching sites and Cam companies to get the best Cam for my 1969 Cutlass Supreme. When I bought the car I was told the engine and trani are 350 builds. After having a few people look at the car and giving me advice, three of the four told me I should double check my engine size because it doesn't look like a small block 350, because it looks like a big block. So now I need to figure out where and how to identify the size of my engine before I get the Cam. Thanks for your help.

 

The quickest way is to look at the bottom left corner of the cylinder head as you face it. If there's a letter, it's a big-block; a number, a small-block.

Search the oldswiki on this site for additional ID cues.

 

First of all, to the uninitiated, the small block and big block Olds motors look exactly the same. The main external difference is the deck height (big blocks have a taller deck to accommodate the longer stroke). Because of this, the intake is about 14" wide on a big block vs. about 12 1/2" wide on a small block. There is a block casting number located on the small shelf above the water pump, next to the oil fill tube. Casting number ID is found here:

http://www.oldsmobilewiki.com/index....ategory:Blocks

And by the way, all Olds small and big block motors accept the same camshafts, same timing gears and chain, etc. The pushrods are different again because of the deck height.