Quote:
Originally Posted by Mister Pontiac
Rocky,
Just to add in another bit of possible confusion, I have a base YH 428 out of a 67 Grand Prix that appears to me to be blank (no stampings). I double checked again today just to be sure, and I can't find any stampings. The heads do have some rust on them, but after wire brushing the area, I cannot see any remnants of a stamping on either head. So...
To the best of my knowledge, this engine has not been apart since it left the factory 50 years ago. From what I understand (from a fellow PY'er I bought it from), it was pirated from a 67 GP back around 1971 following an accident that destroyed the car. After that, it sat in two different garages for 40 years untouched before I bought it and installed it in my wagon. It still has not been apart.
So if its history is accurate, mine in a base 428 out of an automatic GP, yet it has no stampings (blank).
Hmmm...  |
Thank you for the info!
So the question now remains, was "unstamped" used to denote the GP's 400 and base 428 4bbl cylinder head assembly up to a certain point? And was the "O" assembly that may have been dedicated toward GTO and Firebird 400 automatic applications eventually used on the on the GP's 400 and 428 4bbl, effectively eliminating the need for the "O" stamped casting entirely?