[73T/A]

I purchased a set of 1971 455 H.O. cylinder heads casting 191 about 25 years ago.A individual was selling these heads and other parts for an acquaintance.These heads are essentially configured like 455-SD heads +.They have pushrod tubes and the valve cover bolts and rocker studs both are through the intake port roof.Combustion chamber size is 92cc that’s after I had hardened valve seats and new stainless valves installed.Chamber was most likely smaller than that before.Also during the purchase the seller then notified me that those heads were special and came out of Pontiac and were not supposed to be sold.I mentioned that I had already mailed the cashiers check a week ago.He then talked the owner into letting them go.These heads are stamped on the back of the head RUSS with looks like a work order number 10750 this is on both heads same location.On the front of the heads are the number 2 stamped four times almost in a rotating cross pattern.Russ Gee was one on engineers on the SD 455 and was also head of the Pontiac Dyno rooms maybe RUSS stamp?And the number 2 stamps may represent Pontiac motor division which Pontiac used on VIN’s etc as a identifier.Or all this could just be a head porters stamps.What do you think?

[Dragncar]

It looks like you have a set of the heads Dan Whitmore told me about. There were supposed to go on a 10-1 SD 455 with 4 bolt block, forged rods, forged pistons, RAIV valvetrain and cam, pushrod tubes, 850cfm Q jet, aluminum intake. You have a part of history, wanna sell them ?
These are the heads that Chevy nixed because it would have blown away the LS6. Dominating the streets.
Congratulations !
Dan said there were 2 to 4 sets. One of the engineers he knew brought them by his shop to check out.
These heads with larger chambers because the 73 SD 455 heads. Those engineers did not want all their work to go to waste. Pontiacs last gasp.

[73T/A]

Originally Posted by Dragncar

It looks like you have a set of the heads Dan Whitmore told me about. There were supposed to go on a 10-1 SD 455 with 4 bolt block, forged rods, forged pistons, RAIV valvetrain and cam, pushrod tubes, 850cfm Q jet, aluminum intake. You have a part of history, wanna sell them ?
These are the heads that Chevy nixed because it would have blown away the LS6. Dominating the streets.
Congratulations !
Dan said there were 2 to 4 sets. One of the engineers he knew brought them by his shop to check out.
These heads with larger chambers because the 73 SD 455 heads. Those engineers did not want all their work to go to waste. Pontiacs last gasp.

I plan on keeping them for a while as they have been on my 462 in the 73 T/A.When I purchased them way back when I was just looking for a set of round port heads and these popped up.Other than verifying the 191 casting numbers I never looked for any other identifiers until recently.When I had them freshened up the machine shop was sure curious about them.I wish I would have put them on a flow bench.

[JSuchma]

A long-time friend and high school buddy of mine has a pair of 191 heads that he got from H.B. Bailey, the early '70s NASCAR driver for Pontiac. They have 72cc chambers and Pontiac engineering stampings. Maybe someday he will let me get a few pictures of them for posting. I won't hold my breath.......I have been trying to buy them from him for years.

[johnta1]

Is there a cast date on the heads?

[JSuchma]

Yes.........191

[73T/A]

Originally Posted by johnta1

Is there a cast date on the heads?

Head casting number on mine is 191.The date is hard to read on mine.Looks like maybe A07 January 7th but the last digit for the year is hard to make out.I will have to try to check it out better.

[scott70]

Originally Posted by Dragncar

It looks like you have a set of the heads Dan Whitmore told me about. There were supposed to go on a 10-1 SD 455 with 4 bolt block, forged rods, forged pistons, RAIV valvetrain and cam, pushrod tubes, 850cfm Q jet, aluminum intake. You have a part of history, wanna sell them ?
These are the heads that Chevy nixed because it would have blown away the LS6. Dominating the streets.
Congratulations !
Dan said there were 2 to 4 sets. One of the engineers he knew brought them by his shop to check out.
These heads with larger chambers because the 73 SD 455 heads. Those engineers did not want all their work to go to waste. Pontiacs last gasp.

I bet my 9.7-1 ported iron d ports head, iron intake, iron exhaust manifolds could beat a stock ls6 of the day. Those rectangle ports were huge.
Those are some cool heads there,, 92 cc you could make close to 10-1 on a 455 with a 0 deck and a head gasket of around .035.

[PAUL K]

Some better pictures would be helpful.

All original service RAIV and early 197 heads didn't have date codes. It'd be a bit odd that the 1970 RASD head would have them.

From what you can see of the intake flange rail they look thin in the pictures. Possibly because the intake side was milled to match the deck. H-O heads could be safely milled to 91-93 CC.

The exhaust ports look heavily ported, a lot more than the heads that were ported by the shop modifying them for the Pontiac engineering department.

It wasn't uncommon for a head porter to install the SD455 sleeves for the same reason Pontiac did. They were available over the counter and easily obtainable.

Not sure why RUSS would have his name stamped on the heads unless he was afraid of loosing them.

The four 2's definitely looks like something the engineering department may have done but they were pretty slap happy with the numbered punches and like to use X a lot.

[73T/A]

Unfortunately with the heads installed and engine in the car I’m out of luck on pictures on the intake side.As mentioned under the RUSS stamp there is a series of numbers maybe work order?I have seen machine shops stamp their business name on ported heads such as my D ports that were ported by Dave Bischoff they have SD Perf stamped on them.I have never heard of a company by the name of RUSS doesn’t mean they don’t exist.Or could be a individual head porter.But Russ Gee was the head of Pontiac Experimental engines and involved with the SD-455 program.I read were Pontiac was sending some of there experimental heads to Diamond Engines for head porting.This was in a article on Jim Wangers 1968 Firebird (Black Bird) street racer.

[steve25]

Pontiac engineering U.P.C codes tell the progression of engine development and the time span of usage in many cases.

The code only changed when significant changes were done for the most part.

A few brief examples.

L-74. All high comp 400 4bbl medium performance motors from 68 to 70.

L-78 all low comp 400 4 bbl medium performance motors from 1971 to 1979.

L-67 1968, RA1 D port, RAII round port, so where into the round port era now.

L-67 1969 and 70, RA4 motors except in the F body .
These RA4 engines in 1970 got a LS-1 code

L-75 base line 455 engines.

LS-5 1971-72 455 round port HO.

LS-2 455SD.

So the 455SD was in development as early as 1971

The LS-2 U.P.C code is to me the most likely reason for all the number 2 stamping on your heads there.

Note that once engineering got to making a 455SD 16 preproduction casting that they put the air injection boss back in across the top of the exh ports in case they needed to add a air pump to meet emissions.

Here are molds of an Intake and Exh port from a non ported 455SD production head.

[jamaca85]

look up the name Russ Flagle...Indy cylinder head. call them and see is that's their stamp. he is no longer alive but maybe somebody there might know

[steve25]

Was Indy cylinder heads even around in the early 70s?

[Half-Inch Stud]

Looks like RA II combustion chambers. Maybe RA IV chambers?

Anyway exterior looks RA II, yet the 191 and no R 96 A reveal design intent for differences. Are they just 191s with high compression?

[PAUL K]

Originally Posted by steve25

Was Indy cylinder heads even around in the early 70s?

No nut Russ Flagle was

[mgarblik]

Russ of Indy Cylinder head fame really hated Pontiacs. It would be a stretch IMO that he did port work on Pontiac heads. I base this opinion on having several Edelbrock Pontiac heads repaired by him and the shop in the 1990's. We took the destroyed by nitrous heads to him and he spent at least half an hour telling us we were morons and idiots for doing anything with a Pontiac engine. Then he tried to scare us away with a very high price to weld them back together. When that didn't work they proceeded to weld up the chambers, weld up 4 destroyed seat areas and honestly make them look like new again. Nicest aluminum repairs I have ever seen. Sometimes you have to put up with allot of abuse to run a Pontiac. But his general disdain for Pontiac engines makes me think it's unlikely he had his hands on your special Pontiac heads. Thinking Russ Gee is more likely. Hope you find out the whole story. Special heads indeed!

[Skip Fix]

The local guy I bought my SR RAIV heads from in the late 80s worked at a Pontiac dealership in parts had a 79 TA he street raced that had some 71 HO heads he said had 72cc chambers from the factory as cheater heads. Solid roller cam Warrior single 4 intake used McCreary sticky dirt tires and would pull the front wheels on the street. Heard the windshield popped out of the T top car on one launch.

[steve25]

I thought I read that it was Waren Brownfield that helped with the development of the 455SD heads, and this would have of course been before AFR.

[steve25]

Just to keep all our Ducks in row here and to reinforce what Paul had in an earlier post the casting number is 197, not 191.
The full part number of the head was 481197.

[73T/A]

I have some updates on the 197 455 H.O. cylinder heads..Cleaned up the forward and aft head surfaces along with the date code areas also used my borescope to get a better look at the aft sides by the firewall.Here’s what I discovered.I was incorrect on the info in regards to the number 2 stamps.For some reason I thought that both heads had that.Turns out one head has the number 2 stamps and the other head has number 1 stamps.Both heads are stamped at the same location and font.Both heads due have the RUSS stamped with the same numbers below same font.In another twist I found a much smaller stamp of 12/89 in a different mix match font with what looks like possibly light crude etching.I also was able to read the date codes.L 08 0 on one head.The other head looks maybe like A 07 and last digit looks sort of like a 7 or part of a 0 not sure on that one.Would Pontiac have been casting SRS 197 round port cylinder heads as late as January 1977?