1963 340HP L76 Engine Intake Manifold Gaskets and Seals

[Richard M.]

Here is a compilation of photos of some of the parts I removed from a very original 340HP L76. Just for futire reference before I forget to put it all in one thread.

Before....
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The intake manifold end seals. The GM tabs were broken off years ago, but orange paint still seen on the edges of the seals and the aluminum intake.
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The removed intake manifold gaskets. Note the FELPRO in a diamond. Bob Jorjorian and I discussed this and we both feel that both Victor Gasket and Felpro supplied gaskets to GM, and likely Flint Assembly. Also note the semicircular tab near the exhaust crossover. The word "GM" could not be seen whereas it is typically at the water outlet area. These have been compressed too long to see it.
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Bob sent me these photos of his NOS Victor Gaskets. Note the "V over the "G" (VG) and note where the "GM" impression is.
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These are some close-ups of the seals I removed. They were brittle and caused a massive front area oil leak. The broken tab areas are visible along with old orange paint.
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Rich Mauser sent me photos of his NOS end seals but I have to get them from my other computer. I'll post them later.

Here are some other interesting features on some of the other parts....
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Fear not.... I replaced the bulging soft and spongy bypass hose with a nice GM NOS service replacement. Original clamps were reused.
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On reassembly, I tried to maintain the level of originality by not performing any abrasive cleaning or using solvents of any kind. It was all carefully cleaned to keep it looking as original as possible. NO NEW paint anywhere.

Rich

[Bob J.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Rich,
Thanks for posting the pics.
That is a VERY hard to find throttle lever rubber bushing. Most are long gone or in pieces.
Does the throttle lever ground strap hole have threads in it? I know it is a no radio car..... I'm just curious.
What marking is on the rocker arms?
Bob Jorjorian

[John D.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Jorjorian, My 63, the LWC has one of those ultra rare "geared" throttle lever rubber bushing. One of the few I have ever seen. It's not perfect but good enough.
Remember I sent you a pic of it years ago? JD

[Richard M.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Bob/John, I'd never seen the rubber bushing like that before. It has those interesting gear teeth in it. I never knew they existed. When I removed the cotter pin to remove the intake, I swear I was the first to touch it since it was installed in 1963.

Yes the car is definitely a no-radio car. Perfect white fiberglass under the rear deck with absolutely no sign of repair or replacement.

There are no threads in the throttle lever. Also no threads in the frame crossmember holes where the ground straps would normally be attached to the exhaust. I looked very closely.

Rich

[Mike E.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

That toothed bushing was on 62's also. I've seen several, and both my bow tie 62's still have them. I'm glad someone else recognizes their validity.

[Mike M.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

i've removed some of the toothed rubber bushings from 62-64 full size junkyard chevys. i find them rarely compared to the non-toothed rubber bushings during my junkyard ventures. i suspect both varieties were used on chevy/corvette assembly lines during that time period. none of the 35 or more c-1 and c-2 vetoes i've owned have had such an animal. mike

[Richard M.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Another note about this no-radio example...

When I removed the FUEL/BATTERY gauge pod to have them repaired at Bill Harrison's shop, I saw 2 capacitors under the dash. One was attached to the Park Brake switch, and there was also one for the Stop Light switch. Both had been there forever by the looks of them.

I would suspect that both assemblies had them installed before they got installed in the car. Even though the car had no radio. There were no capacitors mounted to the instrument cluster or the coil bracket nor the voltage regulator.

I did see one ground strap. The one from the left front birdcage to the frame.

Rich

[Alan D.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Good to see another bypass fitting with only the "P" in the diamond, the JG calls for "CP"

[William F.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Where is this geared rubber bushing?

[Timothy B.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Bill,

It's in picture #5 that Richard posted where the throttle rod goes into the lever. I had one like that on my 67 and I thought someone else put it there.

[Joe L.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Bill,

It's in picture #5 that Richard posted where the throttle rod goes into the lever. I had one like that on my 67 and I thought someone else put it there.

Timothy------


I don't understand why you would have had this style bushing on a 1967. The 1963 Corvette accelerator rod bushing was GM #6257135. This was actually a bushing that was first used for the control regulator rod for 1961 Chevrolets with cruise control. It was subsequently used in PRODUCTION for the accelerator rod bushings 1962-63 Corvettes. It also became SERVICE for many earlier Chevrolet accelerator rod bushings. However, it was discontinued from SERVICE in October, 1963 and replaced by GM #3794377. The latter is a "non-geared" style bushing and remains available from GM to this very day.

The 6257135 having been discontinued more than 52 years ago, I'm not surprised it's hard to find in NOS condition.

[Leif A.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Joe et al,

What was the purpose/reasoning behind a "toothed" rubber bushing?

[Joe L.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Joe et al,

What was the purpose/reasoning behind a "toothed" rubber bushing?

Leif------

I have no idea. However, it was replaced with a "non-toothed" bushing so, apparently, the original configuration was deemed unnecessary. The "toothed" bushing was only around for a couple of years. Its non-toothed successor has been around now for over 52 years.

[Richard M.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Here's a cropped closeup....I wish I got a clearer view but that wasn't the focus point when I took the photo as it was the intake seal I was concerned with.
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I can see no mechanical advantage over using it. It wasn't filled with grease, as grease and rubber are a bad thing. And since the metal accelerator rod to plastic bushing is the friction point, the plastic bushing was not designed to rotate in the rubber.

The only other reason I could think of, as far fetched as it may be, is cost savings. It used less rubber to make it. If these were devised and used on the passenger car and truck line for a few years, at millions of vehicles per year, add up the materials savings and the bean counters probably loved it. Whenever I see a part that doesn't make sense, it usually has to be a cost savings issue.

Just another mysterious little part that only the originators had knowledge of.......

Rich

[Timothy B.]

Re: 1963 340HP L76 Engine Intake Manifold Gaskets and Seals

Joe, I could swear that toothed bushing was on my 67 car, I know it was not in good condition and replaced it with the smooth style. I will check if I saved the part.