[Schurkey]

Originally Posted by Formulabruce

On 455 blocks made in 75 and 76 you can find huge discrepancies in the rough cast area where the original rope seal sits. This can make indexing a new style seal impossible. Most of these cast SEAL areas are NOT concentric with the crank. My machine shop owner and I did a AERA bulletin on this. 75 and 76 blocks ONLY.

I've known about the non-concentric seal grooves in Pontiac engines for years--read about it most-likely on this very forum.

I did not realize it was limited to 455 only, and '75--'76 only. I thought it was Pontiac engines in general--some were made concentric enough for a lip seal, and some weren't.

Glad to know it's more limited than what I previously believed.