[shermanator2]

I would like to put stock length valves in 9770716 heads. I can not find anyone out there that lists replacement valves for the pre-1967 heads. Anyone know of a source?

My old Perfect Circle catalog shows the over all length to be 4.885" for the intake and 4.895 for the exhaust. I measured the probably original valves in another set of 9770716 heads and they were 4.902 intake and 4.890 exhaust.

The only thing close that I can find are the ones that Butler sells and are listed as 4.980". Is that my only option? Am I missing something here or are these really 0.080 to 0.090 longer than the originals?

Is there a reference or a thread on this forum that lists all of the lengths and head diameters that Pontiac used over the years? It would be interesting to put something together with the various valve dimensions, associated push rod lengths, and applicable cylinder head castings.

[25stevem]

Egg auto parts list a S2543 Pontiac exh valve at 4.830” which will work, the hard part is the intake valve.

What I would suggest is a easy to get 2.02” SBC Intake valve which is 4.880” long and then have your shop cut it down to the 1.920” if you want to keep the 30 degree seat, or get a 1.940” SBC valve if your going over to a 45 intake seat.

The old TRW number is V2470 for the 2.02” valve, the 1.940” valve old number is V 2351N which is polished.

[b-man]

Here’s the part numbers and specs of the valves that were cut down to the correct head diameter to fit my 9770716 heads.

8 ea. 6000SG S.I. Stainless Intake Valves - 1.960" x 4.970" - $128.00
8 ea. 6001SG S.I. Stainless Exhaust Valves - 1.660" x 4.970" - $128.00

The valve heads were cut down to 1.93" and 1.645" respectively to eliminate any possible valve head to valve head interference. The original valve sizes were 1.923" and 1.663" according to factory specs.

[shermanator2]

Thanks 25steveM and b-man for the replies.

Steve, I am not familiar with Egg Auto Parts. Who is that? In any case though, I think that 4.830 is too short.

So b-man, your reply is interesting and informative as always, but brings up a couple of other questions.

Is valve to valve interference an issue with 9770716 heads? I think that the C to C of the valves is 1.820” and with the original sizes that you state, that leaves nominally 0.027” between the valve heads. I can see a few thousandths of slop in the valve guides and some tolerance in the spacing, but it does not seem like they could touch.

Why did you chose the diameters that you did? Specifically why did you make the exhaust valve so far undersize and then the intake oversize?

Do you agree with me that the original lengths were something close to 4.890-4.900? Do you have the factory specs for that? The valves that you used are 0.010” shorter than the Ferrea ones Butler offers, but am not sure it is worth doing something custom to gain back only ten thousandths.

[54nomore]

It's Egge Machine actually. You might also check out Kanter Auto.

[b-man]

Originally Posted by shermanator2

Thanks 25steveM and b-man for the replies.

Steve, I am not familiar with Egg Auto Parts. Who is that? In any case though, I think that 4.830 is too short.

So b-man, your reply is interesting and informative as always, but brings up a couple of other questions.

Is valve to valve interference an issue with 9770716 heads? I think that the C to C of the valves is 1.820” and with the original sizes that you state, that leaves nominally 0.027” between the valve heads. I can see a few thousandths of slop in the valve guides and some tolerance in the spacing, but it does not seem like they could touch.

Why did you chose the diameters that you did? Specifically why did you make the exhaust valve so far undersize and then the intake oversize?

Do you agree with me that the original lengths were something close to 4.890-4.900? Do you have the factory specs for that? The valves that you used are 0.010” shorter than the Ferrea ones Butler offers, but am not sure it is worth doing something custom to gain back only ten thousandths.

I let the machine shop doing the work on the heads (along with the 421 short block) decide what to do to make everything work. A small deviation from the factory sizes wasn’t anything to be concerned about.

Perhaps it was because of the expansion rate of the stainless valves compared to the factory valves that are essentially unobtainable, I’m not really sure.

According to my copy of Pontiac Heavy Duty Parts & Specs by Craig Hendrickson & Kern Osterstock of H-O Racing Specialties, Inc. published in 1976 Revised 12/78, the intake valve for 1964-66 3/2BC was p/n 546392. Diameter is 1.92 and valve length is 4.797.

So there you have it, at least from one of the most trusted and reliable sources. I’m sure anything that’s close enough in length to the valves you took out of the heads will work fine. My machine shop was well versed in engine building for competition and I trusted them along with my friend who was entrusted with the actual engine assembly, that they would handle everything to my expectations and beyond.

Link to my 421 HO engine build thread in the ‘61-‘66 Big Pontiac forum if you’re interested:
https://forums.maxperformanceinc.com...d.php?t=774638

[Joe-Touring]

I bought these for my early heads:

https://www.summitracing.com/parts/mil-45490-8

https://www.summitracing.com/parts/mil-45495-8

On the spendy side, price has gone up since I bought em.
Haven’t installed em yet, waiting for my other engine to be done before tear down.

[shermanator2]

Originally Posted by Joe-Touring

I bought these for my early heads:

https://www.summitracing.com/parts/mil-45490-8

https://www.summitracing.com/parts/mil-45495-8

On the spendy side, price has gone up since I bought em.
Haven’t installed em yet, waiting for my other engine to be done before tear down.

That got me excited because those are almost perfect. I called Milodon and found out that their intake valve is 45°, not normal Pontiac 30°. So close.

[25stevem]

Even the Milodon site does not state if those 45490 are 30 or 45 seat valves.

[b-man]

Originally Posted by shermanator2

That got me excited because those are almost perfect. I called Milodon and found out that their intake valve is 45°, not normal Pontiac 30°. So close.

A lot of the factory Pontiac heads equipped with 1.96” intake valves had 45 degree intake seats.

[shermanator2]

My seats are already 30° and as I understand it, 30° flows better at low lift. I am going to be using an 068 cam probably with 1.5 rockers so I think 30° will be best.

After thinking about this and sketching it out, I think that I can just reface these to 30°. I need to cut them down to 1.92 anyway. I think that I will order a set and give it a shot.