[wayne228]

As I said last month I am cleaning up the garage & coming across long forgotten parts. I have located a head with part numbers I can not figure out. the head number is 7 digits long. I can make out all but the third & fourth ones,. It reads as follows 9 7 ? ? 4 5 6
The third digit looks like it could be a 8 or a 9 , and the fourth digit could be a 5 or a 6 .
Based on the info I know -
1967 should be 9778692 or 9778693
1968 should be 9791194 or 9791195
1968 should be 9790826 or 9792539
If the third digit is a 8 I'm lost....
Now if the third digit is a 9 that puts me into a '68 or '69 but the last 4 digits have me stumped ( 5456 or 6456 )
Anyone ever come across a head with this series of numbers?

[Jeff Hamlin]

Looks/Sounds like a 1969 head...
9795458 69’ 1BC.
9795457 69’ 4BC

[wayne228]

I was leaning that way but the 456 threw me off. Could the last digit being a 6 mean it was produced for a LaMans or Tempest ? Or does that not matter at all ?

[Jeff Hamlin]

I don't think they grouped by model (i.e. Tempest Vs Firebird),
but can't say that with authority. The numbers I have on file have been confirmed only by year off Heads I have physically documented and/or have had.

The 3rd/last group you list (9790826 or 9792539) I have not seen before.
If you know for sure these are verified 1968 numbers then a 1969 (9795456) might be possible, or it's just a poor cast 6??

Numbers I have filed;
9782005 66’ 1BC. 9782229 66’ 4BC
9778692 67’ 1BC. 9778693 67’ 4BC
9791194 68’ 1BC. 9791195 68’ 4BC
9795458 69’ 1BC. 9795457 69’ 4BC

Anyone with other castings numbers please chime in.

Cheers

[wayne228]

The third set of head numbers came from The Definitive Firebird & Trans Am Guide by Rocky Rotella. They should show as Cams not Heads (sorry, I noticed it too late to edit the comments ) THE THIRD LINE SHOULD HAVE READ: 1969 9795458 1Bbl 9795457 4Bbl
Other numbers I have from working with them are same as you show.
The only odd ball is this head with the 9 7 9 5 4 5 6 or 9 7 9 6 4 5 6
I cleaned it a little more & am reasonably sure the third digit is a 9 now.
Is it possible it could be a service replacement ? I have never seen a 56 before this...

[Jeff Hamlin]

In all the 35+ years I've been Picking and Parting OHC's I have only come across 1 SR engine. It was out of a '67 FB and had/has a '67 Casting #.

[camerjeff]

Thanks for the pictures of that SR Block, I have never seen one myself, and at one time I had over 30 engines in the shed.

[John V.]

I'm no expert on the OHC-6 engine but somehow I think you guys are crossed up.

9795456 is the common '69 1 bbl OHC-6 head casting.

9795457 is the '69 4 bbl OHC-6 head casting.

I'm guessing that the last character "6" has often been misread as an "8" leading to the mistaken identity of the 1 bbl head as 9795458.

Just like for some of the very early '69 V8 heads, some early '69 4 bbl OHC-6 engines got the carried over '68 heads with the 30 deg intake valve seats (casting 9791195), the "true" '69 versions got a 45 deg intake valve seat (casting 9795457).

I believe that only applied to the 4 bbl, the '69 1 bbl only used the 9795456 casting.

While previous convention is not proof, it is at least worth noting that the '67 OHC-6 heads were consecutively no. as were the '68 OHC-6 heads and in both instances, the 1 bbl head was first, then the 4 bbl.

It would stand to reason that the same thing was true for '69, ie., 9795456 as the 1 bbl head followed by 9795457 as the 4 bbl head.

Pontiac did not service bare head castings so unless you have access to the original engineering drawings for the head castings, you will not find the casting p/n in any literature such as PMD Service Parts Master Parts Catalogs. On rare occasion, a PMD document will identify bare head casting p/ns for the purpose of identification. Perhaps such a document exists for these OHC-6 head casting p/ns.

I could be wrong, but I believe my explanation is the logical one in the absence of other evidence.

[Jeff Hamlin]

John,
Your spot on I can't believe I overlooked this for so long.
Just the sequence alone should have been a flag to me

Thanks for enlightening me.
Cheers.

[wayne228]

Ok, that makes sense John...Sometimes you truly can not see the trees for the forest gets in the way. The last casting number could very easily be mistaken for an 8 . The idea of the sequence following true for 69 (higher digit = 4Bbl ) should have been a no brainer ! Anyone else have the sequence numbers for the 1966 engines ? I am wondering why they do not seem to follow this sequence ( based on Jeff's numbers above )

[John V.]

I believe Jeff has the '66 head casting p/ns correct.

I also noticed they are not sequential that year but I believe that can be explained by the fact '66 was the first year.

Likely the 1 bbl engine development was slightly ahead of the 4 bbl, hence the non-sequential head p/ns that year.