Re: BBC casting #1X157129AC still a mystery.
 

I'll take some more good pics and post them later tonight. I appreciate the info so far.

Re: BBC casting #1X157129AC still a mystery.
 

Hello,

Its been a while but it seems that I have seen similar heads used on Mercruiser versions of LS-6-7 engines in the 80s.

The ones I saw had closed chamber style domed pistons, that looked very similar to a 1970 LS-6 forged 11.0 to 1 (with a closed chamber head), but used the open chamber rectangular port head.

Im not sure about the intake valve size but the exhausts were 1.88".

Maybe these have a marine origin?

Competition Products, in Wisconsin used to do a lot of work on Chev marine engines in the 80s, and would sell a lot of take off stuff in the Dragster. I bought "L" rockers, cams, intakes, balancers. etc.. Maybe they would know a little about this?


Jeff