http://www.ford-y-block.com/ltcastnub.jpg

See if this link takes you to the top right of the 3 pictures. Try there, it’s tough to see on the engine or in the car, even worse if not clean.



Don’t get hung up looking for “312” numbers, even if you’ve checked the main caps. Lots of parts got substituted over the years. My first 312 had mismatched heads.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks that is where i found  them there are no other numbers 6090 under valve cover 60 A and C69 between exhaust portes. no date codes ?
  

There’s some pictures of where to look, and the casting numbers here

http://www.ford-y-block.com/cylinderheadchart.htm



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I have a 57 312 the only numbers I can find on the heads are 6090 under the valve cover I no thats all ford heads. The left head is 60 A right head is C 69 ???