BBC casting #1X157129AC still a mystery.
 

I posted this last week trying to find some info on this mystery casting number but have come up with zilch, like they dont exist. They have CFD cast in them as well as HI PERF. The date code is only 58. They are rect port iron BBC heads with 2.25 valves and bronze guides. The main reason I need some info on them is I would like to sell them but I dont know which class can use them. They are fresh with new valves and guides and triple springs. Any info would be appreciated.

http://i151.photobucket.com/albums/s...h_DSCF3005.jpg

http://i151.photobucket.com/albums/s...h_DSCF3004.jpg

Re: BBC casting #1X157129AC still a mystery.
 

I think your question was answered here. Their are way more Sharper Guys on this site that live & die by casting numbers. Suggest for you, spend some time over on the NHRA Engine Blueprint Specifications. That head will not be legal for any traditional Super Stocker or Stocker.

Re: BBC casting #1X157129AC still a mystery.
 

Is that an open or closed chamber head? What spark plug does it take?
I knew you said it had a 2.25 intake valve, what size exhaust valve?
Thanks, I wonder if Dwight Southerland can chime in on this one?

Re: BBC casting #1X157129AC still a mystery.
 

I suggest you try and sell them on the Yenko or a Corvette site cause there not legal in stock unless you grind the numbers off and carefully weld on different numbers. Thanx Trevor

Re: BBC casting #1X157129AC still a mystery.
 

They are open chamber with a taper plug. I believe the exhaust are 1.88.

Re: BBC casting #1X157129AC still a mystery.
 

The little plug has to mean post 1970, and the open chamber almost has to lead me to believe it is a prototype of an over the counter item. Somebody correct me if I'm wrong, but I don't think there was ever a production engine built by GM after 1970 that had a big port open chamber iron cylinder head on it.

Re: BBC casting #1X157129AC still a mystery.
 

Bowtie Froggie is correct. These heads are from Central Foundry Defiance. The wagon wheel was the old logo. All Central Foundry Sites became part of GM Powertrain in the early 90's, so I would guess that these heads are service replacement heads from 1988. The date code uses a letter for the month (we didn't use I so it wouldn't be confused with a 1), then 3 numbers. First 2 numbers were the day and the last # was the last number of the year. maybe 058, 158, 258, who knows. looks like the pattern had a "sticker" and the numbers didn't get imprinted in the mold. Defiance finished production of the Mark late last year. (8.1 liter block, head and crank) The end of an era for sure. I will try to find out more about the casting #. Take care guys.

Re: BBC casting #1X157129AC still a mystery.
 

What would a head like this be a replacement for? SS454 truck maybe?

Re: BBC casting #1X157129AC still a mystery.
 

The last BB open chamber rectangular port head I am familiar with was the 188 casting. That was the last 3 numbers. It was found on crate LS-7's in the late 80's I'm guessing. They had 2.19-1.88 valves and one big difference from the previous 990 heads......hardened seat inserts( stellite) on the exhaust side. Peanut plugs as we called them were only on later heads. No production engine installed in a car or truck ever had those heads on them. GM Performance used to build special vehicles for display or use them for promotion. They also seemed to build some pre production stuff to see if there was interest.........Those heads have to be pretty old. My buddy has an original SS454 pickup and there is no way heads like that were on his truck when it was new.....he replaced the engine with a crate 502 a couple years ago.....

Re: BBC casting #1X157129AC still a mystery.
 

Jim - I can't shed a lot of light on this that hasn't already been said. The CFD marking indicates to me these are from the '80s. Maybe this was done at the same time the replacement 291 closed chamber heads were done. I know the late casting 291 heads (which were also CFD castings from the '80s) used the same intake port and exhaust ports as the 188 & 990 heads and were machined for the 5/8" spark plugs. What throws me is the 2.25" valves. Chev had 2.30" valves in their HP catalog about that time, but not 2.25" valves. It would be nice to have a bunch more pictures.