Here are pages that detail engine specifications - I am not a GMC Knowledgeable person, I found these doing a search and thought they might be useful, covers a lot of information regarding engine specs, casting numbers, etc....courtesy oldgmctrucks.com right click on image, open in a new tab, then magnify..
The GMC Heads page has some good details regarding head casting numbers and the model year.
Hopefully a GMC expert will be along shortly to provide more information...
Last edited by Dusty53; 05/10/20222:11 AM.
Ron - - Dusty53 1954 Chevy 3604 In the Gallery Forum "You can't dance with the Devil and then wonder why you're still in Hell." "They will forget what you've said, and they will forget what you have done but they will never forget the way you made them feel."
