Hello Charles, great of you to react very quickly via a PM, but I haven't heared from you since. For everyone reading this post, the 512121 is the L-head for a Pontiac straigth 8, the standard compression head. It's on my 1948 engine. I think I will need a new one but live in the Netherlands, Europe and it's impossible to find one here. The engine is now at the engineshop, we will see.