[Ron Landis]

STILL playing devil's advocate...what if car was going down the line and there were NO #12s on the shelf. Would they stop the line or use an available similar head? I totally agree with what's been said here...just not ready to rule out another possibility. Also...weren't the '69 48s slated for use on the 350 HO motors utilizing smaller combustion chambers? I understood they were somewhere @ 64 CCs...standard 48s @72CCs and 62s @ 75CCs. Was all that bunk as well? I did get to the bottom of the #16/#62 controversy...and it wasn't Pete's fault. It was Ken and Craig's book on parts and numbers. I was told they ordered one of each head per model...and were sent a #16 for the '69 GTO automatic. This was the expalnation presented to me when I launched my inquiry via the GTOAA back in 1987. Take it for what it's worth. Like I said before...locate a set of "correct" heads to save yourself a ton of "headaches"...pun intended. FWIW...ONLY '69 dated #16 was a small valve head found on a 2BBL Catalina wagon. Never seen a '69 dated big valve head with screw-in stids from a documented car. Ron

['ol Pinion head]

Cant say I've ever seen a production set of '69 16 big valve heads. I have seen late dated bare 16 big heads which were shuttled to service parts. The pics Kenth put up shows some maroon paint on the side of the head. Makes me wonder, as several SR 400 fitted shortblocks I've had or ck'ed out (all never installed) had a splash of maroon dye or paint on the front.

Ron, as far as your first sentence goes, assembled cylinder heads were bolted on their correct mating freshly assembled shortblocks at the Pontiac plant engine build plant, then after everything was buttoned up the engines were sent by rail to all the various auto assembly plants. 12's used a different valve & higher pressure valve springs (pink stripe if I remember right) than 13's. YZ's being assembled with 13's doesn't make sense. It would limit performance, just like if we now skip forward to the assembly plant & workers were building a RAIII or RAIV '70 T/A without a PQ turbo 400 which shifts at 5400 rpm at WOT, & they instead built T/A after T/A with a soft shifting turbo 400 that would go in a 400 2bbl Esprit & shifted at WOT at around 4000 rpm. The #12 heads were an important part of the RAIII package, if not enough 12's were assembled, YZ & WS engine production would wait & other higher production engines would be assembled.

Know I've accurately cc'ed numerous near virgin (never surfaced, no sunk valve) 13's & they were in the 78-80 cc range. Stated this shortly after PY Forums was 1st on the Net, when someone was telling a poster to get 13's as they are 72cc heads. Many others who actually cc'ed their uncut 13's have agreed. Over the years, I've also had 48's that measured in the 67cc-70cc range.

64cc... this is pure speculation, but am sure sure there have been some nice low mile unsunken valve #48's that may have been meant for a 350HO or built on a 350HO, and then they were surfaced and came in at 64cc. I've also ead of old school builders milling the snot out of them, ie, Royal Pontiac, etc.

[Kenth]

Originally Posted by Tony69

Interesting topic, does anybody have the specs of the various valve springs used by the factory?

Yes, the specs can be found in:

PONTIAC Racer´s & High Performance Handbook by JOHN ANGELES and PETE McCARTY

also in:

PONTIAC Heavy-Duty Parts & Specs by Craig Hendrickson & Kern Osterstock (H.O. RACING SPECIALTIES, INC.)

and in:

AMA Specifications.

and, of course in the Pontiac Service Manual.

Hope this helps some......

[Tony69]

Originally Posted by Kenth

Yes, the specs can be found in:

PONTIAC Racer´s & High Performance Handbook by JOHN ANGELES and PETE McCARTY

also in:

PONTIAC Heavy-Duty Parts & Specs by Craig Hendrickson & Kern Osterstock (H.O. RACING SPECIALTIES, INC.)

and in:

AMA Specifications.

and, of course in the Pontiac Service Manual.

Hope this helps some......

Awesome, Found them!! Been struggling to get these for a while. Thank you.