[151007]

Does a 64 GTO with tri-power intake built for delivery in California (with option K24 Crankcase Vent) use a different valley pan than non-emission equipped cars?

[John V.]

To my knowledge, all '64 Pontiac V8 engines used the same valley pan cover throughout the entire Model Year regardless of CID or carburetion.

However, I'm not sure of the p/n used for it in '64. Perhaps somebody with a '64 MPC could discover it.

There was a p/n change in '65 to p/n 9778955 which apparently superseded the p/n that I believe was first used for '63.

The '63 would have been the first to use a PCV valve, hence the change from the p/n 538372 cover which appears to have been first used in '59.

Upon its introduction, p/n 9778955 became the Service Replacement for all '59 thru '65 V8 applications and was carried over for use in '66 as well, not sure about '67.

Since there was a p/n change for '65, there may have been a revision to the '65 cover for some reason. I simply don't know. But I'm reasonably certain the '65 cover was not used on any '64 engine even though it became the Service Replacement for '64 applications.

When the K24 positive closed circuit crankcase vent system was to be installed, a couple of Assembly Plant changes to the base engine assembly were specified.

This included swapping out the Oil Fill Cap (the standard cap was to be returned to stock), installation of the hose grommet in the LH valve cover (the plug was to be returned to stock), and installation of the K24 specific PCV valve (the standard PCV valve was to be returned to stock).

Items to be "returned to stock" may have only applied to the "home" Pontiac, MI plant. The satellite Assembly Plants would have maintained no "stock" of engine parts. They may have been required to return them to a Parts Warehouse or perhaps back to Michigan. Depended on whether PMD thought the removed parts were worth it to save.

To facilitate the installation of the CCCV system, a running change was made to the LH valve cover specification at the Engine Assembly Plant.

Prior to January 1, engine assemblies were put together with a LH valve cover without a hole.

On January 1, all cars destined to a Cal dealer were mandated by Cal law to have the K24 installed. Consequently, the Engine Assembly Plant began to substitute the valve cover with the hole provision.

Since most builds still did NOT get the K24 CCCV system, the hole was filled with a plug.

I do not think it has ever been documented when the Engine Assembly Plant switched over from the "no hole" LH valve covers to the ones with the hole in them.

My assumption is that they would have begun to assemble the engines with the valve cover with plugged hole in advance of Jan 1 since there was no way to know if a pre-Jan engine assembly would still reside in inventory after Dec 31. Or they may have supplied the Assembly Plants with the special valve covers so that they could be "converted" as needed. This would have mainly affected the Cal Assembly Plants since most builds sold to Cal dealers were built there. And would only have affected a small no. of engine assemblies that had remained in inventory on Dec. 31. The Plants could have also set any such engine assemblies aside to be used up for non-Cal builds so that valve cover swapping could have easily been avoided.

None of this would matter to you of course if your car was built with the K24 CCCV system, it would have the LH valve cover with hole regardless of whether it came that way from the Engine Assembly Plant or had to be "converted" at the Final Assembly Plant.

And to your question, there would have been no reason to change out the valley cover, just the PCV valve.

If somebody can post the p/n for the '64 valley cover, that would be cool.

[151007]

John -- Thanks for the detailed response! I would prefer an original pan (my engine builder told me my old one was bent) but the engine is going to be put on the dyno within several weeks so I started to peruse the reproductions offered by various vendors. My confusion arose when I looked at the Butler Performance Website and saw that the reproduction pan they were selling for 64-67 GTO's indicated "not for use with EGR intakes." Any idea why or what the difference would be?

[tom s]

the egr intake will hit the early valley pans.Tom

[Tom Vaught]

I believe that the EGR intakes have a different Lower Shape "Cut-out" stamped in the pan vs the 64-67 GTOs.
Therefore you could not install a EGR intake on the early Valley Pan.

Believe that is why Butler has that Installation Note.

Tom V.

[tom s]

exactly right Tom,also a tripower wont fit on the valley pan made for a EGR intake.Tom

[John V.]

EGR (exhaust gas recirculation) was a "next generation" emissions control device.

The PCV system was the first emissions control. It was designed to suck crankcase vapors from the oil pan, vapors resulting from ring blowby. These vapors accounted for about 1/3 of auto emissions. It was an easy first step and in my opinion actually improved engine performance (from a maintenance service standpoint) when compared to the old reliance on the road draft tube to eliminate these vapors. And rather than venting the vapors to atmosphere, in most operating scenarios, they were sucked back into the intake to be burned with the air/fuel charge. In certain situations, the PCV system still allowed vapors to vent to atmosphere.

The CCCV system took it one step further by effectively closing the open venting of vapors in all operating scenarios. But it was still only addressing crankcase vapors.

Other emission control devices soon followed as the laws sought to reduce other pollutants.

EGR was among these. EGR is designed to reduce Nitrous Oxide (NOx) emissions in the exhaust gas. It does this by returning a small amount of exhaust gas back to the intake. The exhaust gas causes a reduction in the combustion temp because the exhaust gas isn't combustible. The engine is less efficient but the result of the lower combustion temp reduced the formation of NOx.

I don't know when PMD first started employing an EGR device but I know they had it in '73, the EPA caught them "cheating" because they designed their EGR system to shut down after a short period of time. The EPA was not happy.

My guess is that PMD did not have EGR until at least '68 so I'm guessing Butler is saying their valley pan will not work with '68 and up intakes. Your '64 tripower intake is NOT designed for EGR.

That said, you can buy the repro if you want but you should also be able to score a used original '64 valley cover from somebody with a junk 2 bbl 326 (ie, an engine nobody needs/wants). Maybe post a Parts Wanted ad here.

[b-man]

Thread with pictures to help illustrate the differences between '64 -'72 valley pans:http://forums.maxperformanceinc.com/...d.php?t=769185

The '73 and later EGR-compatible pans have a large 'bathtub' shaped stamping in the middle to clear the huge EGR projection cast into the bottom of the '73 & '74 intakes. By 1975 the EGR intake design changed considerably and the deep stamping to clear it may not have been needed, but the EGR pans were still used until the end of production.

[Tom Vaught]

Thanks Bart, great refresher link.

Tom V.