I know this is second generation, but maybe you will be interested. I have a set of 1970 Pontiac TransAm Heads for sale. Here is some info:

Year: 1970
Casting #: 64
Engine: 455 H.O.
Exhaust Style:
Intake Size: 2.11
Exhaust Size: 1.77
Chamber Volume: 87cc

They have been rebuilt a few years ago for a project. Sold the car without the heads. They are in great condition and would be perfect for your restoration project in order to complete your vehicle and to date spec. Very rare set of heads. Price: Best offer.

Please e-mail me anytime at: nate.whittier@gmail.com
Thanks!

You need to post a price range and proof of a recent mag check or pressure test of the heads. Too many horror stories of guys buying used heads from forums such as this only to find out they are cracked and NFG. Especially from guys on a highly respected forum who just joined today and have 1 post. I'm just sayin.

1970 Trans Am heads were either RAM AIR IVs or RAM AIR IIIs they didn't use a 455 in 1970 in a Firebird. Sorry. The first 455 was in 1971 and they were the round port 197(191) heads.

Wallace has some info for those heads (GTO and Grand Prix only):



Year Engine HP Engine code Trans CR Cam Head Code BBL Carb No. Misc
1970 455 360 HP WA M 10.25 068 64 1-4 7040267/RA 7040279 GTO / 1970 - only year hi comp 455 Block Casting # 9799140
1970 455 360 HP YA A 10.25 067 64 1-4 7040268/RA 7040278 GTO /1970 - only year hi comp 455 Block Casting # 9799140
1970 455 360 HP YC A 10.25 067 64 1-4 7040268/RA 7040278 GTO /1970 - only year hi comp 455 Block Casting # 9799140
1970 455 370 HP WG M 10.25 068 64 1-4 7040267 GP /1970 - only year hi comp 455 Block Casting # 9799140
1970 455 370 HP XF A 10.25 067 64 1-4 7040268 GP /1970 - only year hi comp 455 Block Casting # 9799140

http://www.wallaceracing.com/enginesearch4.htm

FWIW, 64(d-ports) are good for a 400 build if you want to use pump gas.
"about" 9.25-10.00 cr untouched.