lars

From 1966 through 1969, Chevrolet used a unique exhaust crossover passage in the intake manifold just in front of the primary throttle holes. This system was intended to provide heat to the carb for better cold-weather drivability, and it was used on all Q-Jet equipped 327, 350, 396 and 427 engines in this time period.

To keep the hot exhaust gasses from entering the manifold, a special 3-piece gasket "pack" was used on these cars: First, a high-temperature, composite gasket with the exhaust groove in it was placed on the manifold surface. On top of this, there was a stainless steel heat shield. On top of the heat shield, was a unique 4-hole carb gasket that matched the assymmetrical design of the heat shield.

Failure to use this complete, correct gasket "pack" results in either a massive exhaust leak into the intake manifold, a massive vacuum leak, or a wonderful combination of the two. This results in poor idle performance, erratic idle, off-idle stumble, and poor overall performance. This is a very common problem, because the carb rebuild kits for the '66 through '69 Chevys do not come with the correct carb base gaskets, or they do not come with all of the gaskets.

If you go to an auto parts store, they will not sell you the correct set of gaskets for a Chevy with the exhaust crossover in the manifold. If you know the part numbers, you can get the lower high-temp composite gasket from NAPA, and you can get the heat shield from Holley. But you can't get the right top gasket to match the heat shield.

Due to the number of problems I've been seeing with this, I have made it a quest to find all three of these correct gaskets and to package them in a kit. I found a small gasket company in California that had a bunch of the correct upper gaskets in new-old-stock. So I bought 'em. I have packaged up a bunch of carb base gaskets "kits" which contain all 3 of the correct gaskets so you can correctly install your '66-'69 Chevy Q-Jet with no exhaust leaks or vacuum leaks. Included is a correct hi-temp composite lower gasket, a stainless steel heat shield, and the correct matching upper gasket. I'm not aware of this setup being available anywhere else but here in the Forum. $12 plus $1 shipping. I have 10 kits ready to go right now, and access to 300 more.... E-Mail me if you need more info.
V8FastCars@msn.com

marky mark

I'm in!!! But, you already knew that. Great detective work on your part. That would explain why I couldn't find one...They stopped making it! DOHHH!

Thanks again Lars, You 'da Man!!!

Regards, Mark H. :flag :chevy

BB68Vett

Lars, so the Fel-Pro 60043 carb base gasket is not correct for my '68 427? I used to use two 60043 gaskets with a metal gasket in between that blocked off the exhaust crossover to the carb and helped with eliminating heat soak. I believe my engine builder has plugged the manifold holes now but I still use the "sandwich" set up to prevent heat soak in the summer.

Flareside

Hi Lars. Here's the setup that was under the Q-jet that I sent to you earlier this week. Right or wrong?

lars

BB -
Yes, the 60043 is the correct gasket for the bottom of the "pack." The metal shield goes on top of it, and then another gasket - one without the heat slot in it like the one Flareside shows to the far right above - goes on top of the metal gasket. The 60043 will work as the upper gasket, but it's not "correct."

Flareside -
You have two of the gaskets. The ones you show are the two upper ones, but you're missing the 60043 lower gasket. You want that one to assure a leak0-free seal.

Flareside

Lars, the third gasket is still on the manifold in the picture ;)

Is the upper gasket the one that's hard to find? Is it correct? Mr Gasket, $2.95 from Summit, part number MRG-56. Your package is a great deal with the stainless heat shield at $12. Zip wants $12 just for the heatshield!

-Joe


[Modified by Flareside, 10:14 AM 12/20/2001]

lars

Joe -
Okay - I see it. Yep - you got the right setup - 100% correct with all 3 pieces installed in the right order. Yes, the top gasket is the one you can't get from NAPA or most other sources, and nobody will sell you the entire 3-piece setup if you walk in to a parts store and ask for a carb base gasket for a '69 427. Try it sometime and see what you get.... your car won't run with what they sell you..! And the correct gaskets are not contained in the carb kits. Amazing, or what..?

Yes, my little kit is a flamin' hot deal with all 3 for $12 plus some change for a stamp. When I added up my cost on the parts for the "kit," I have a $2 allowance for the gasket that you state Summit sells for $2.95. Have I ever offered anything but rediculous deals here on the Forum...?? Good thing I'm just in this for the fun, eh?


[Modified by lars, 9:37 AM 12/20/2001]

clem zahrobsky

the gasket with the heat slot must be of hi temp material and have metal inside to prevent blow out from the exhaust pressure. regular gasket paper will not hold up for long.

lars

Clem -
Yes, that's right. I've seen versions of the lower, slotted gasket that are not made of the composite construction. These gaskets will burn up, blow out and cause problems, just as you point out. The gasket in my gasket "kit" is the correct one made from high-temp material with the metal center. Correct, good quality stuff.

lars

I'm taking the liberty to do the ttt thing just to make sure everyone sees this stuff on the gaskets.... :cheers:

marky mark

ttt

princeRed72

So Lars this gasket kit was used for all 69 350 Vettes? My friend has a 69 350/350 4 spd. He has had the carb rebuilt and it runs pretty good but i don't recall what the gaskets look like

lars

The exhaust crossover under the carb was used from '66 through '69 on 327, 350, 396, and 427 Q-Jet equipped engines, but not on ALL engines. You just have to lift the carb up and take a look at the manifold to see if the exhaust crossover groove is there. I just did a '69 350 Camaro engine that did not have the groove, but a '68 327 I was working on did. Go figure. If you have a Chevy in this age bracket, it's a good idea to check for the groove, and then check to see if the gasket "pack" is correct. It's also a good idea to verify that the lower gasket you have - the one with the crossover groove in it - is in fact a high-temp composite gasket. I have seen this lower gasket provided in some carb kits, and it's a plain cardboard/paper gasket. A plain gasket used as the lower gasket will eventually burn through and start leaking.

dladd74roadster

Ok Lars, I have another question for you. I have a 1966 Holley equipped 396 Caprice. Does it have the same type of exhause crossover? I have had the carb off of it several times but don't remember. I would go out and look but it is in storage remotely. If it does have the same type of crossover, are those gaskets also as hard to find as the ones for the Qjet?
I know this is outside of the realm of this discussion but if you know, any information would be appreciated.

Thanks
dl

lars

dladd -
Yes, some Holley-equipped factory setups in this same time era also had the same exhaust system under the carb, and a similar gasket "pack" must be used. I have not done any research into the availability of the square-bore gaskets of the same configuration, but I'll bet that the auto parts stores are just as clueless about the Holley gasket pack for these cars as they are about the Q-Jet system...