1963 Corvette Gas Cap Info Please!

[David S.]

Hi Guys,

I'm trying to obtain information in regards to 1963 Corvette Gas Caps. I was told there are two designs. Please verify.

The first design was used up until VIN 16,000. Apparently, it was a vented cap without the rivet pined over on the inside. Also without that rivet on the inside there was a cone shaped raised spot (unlike the later caps that it flattened out).

The second design was late 63 - 67. Please verify.

Also if someone could post pictures of the first design that would be extremely helpful.

Thanks,

Dave

[Joe L.]

Re: 1963 Corvette Gas Cap Info Please!

Hi Guys,

I'm trying to obtain information in regards to 1963 Corvette Gas Caps. I was told there are two designs. Please verify.

The first design was used up until VIN 16,000. Apparently, it was a vented cap without the rivet pined over on the inside. Also without that rivet on the inside there was a cone shaped raised spot (unlike the later caps that it flattened out).



The second design was late 63 - 67. Please verify.

Also if someone could post pictures of the first design that would be extremely helpful.

Thanks,

Dave

Dave-----

I'm not sure about the changeover point but otherwise it's pretty much as you describe. The first cap, GM #3820865 had no internal pressure/vacuum valve-----just a simple hole for venting "either way". The second cap, GM #3843576, had an internal pressure vacuum valve and can be identified by the features you described on the underside. The 3843576 was thereafter used through early 1968.

[Michael F.]

Re: 1963 Corvette Gas Cap Info Please!

The earlier unit had a roller latch and the later unit had the blade type latch used through 67.

[John D.]

Re: 1963 Corvette Gas Cap Info Please!

Michael, I believe they are talking about the gas tank cap and not the filler door.
David, I have always been into the 63 caps no matter where they are on the car. Personally I have never seen but one gas cap-one design on all 63's.
A late 63 I once owned was #19426 (easy to remember as 426 was my Mom's house #.) It had the same gas cap as my 9900 plus 63. JD

[Tom H.]

Re: 1963 Corvette Gas Cap Info Please!

The earlier unit had a roller latch and the later unit had the blade type latch used through 67.

Michael, I believe the OP is referring to the actual cap and not the door.

Here is the latest from my 5th edition JG.

[Stuart F.]

Re: 1963 Corvette Gas Cap Info Please!

I agree with John on this one;

The cap from my original ser#19147 has just the vent hole in a dome on the underside, along with the "SM" in concentric circles logo. On top it is stamped "VENTED" and is zinc plated. Mine is in like new condition because I had replaced it with one of the dealer bought chrome locking caps early on. This past year, in an attempt to control the gas fumes problem, I replaced that cap with a new one from Chevy part #3952708 which has the internal check/relief valve assembly and appears to be cad plated. This cap, I believe, is still available through GM. Mine came by special order from the Atlanta warehouse (?). Took a day or two.

p.s. I did drill enlarge the vent hole in my original slightly, so any picture of it would be sort of non-original - if you could detect it. I keep the locking cap with me for cruise in parking, even though you can open it with a nickle.

Stu Fox

[Jack H.]

Re: 1963 Corvette Gas Cap Info Please!

Here's a pix of the bottom side of that elusive early '63 gas cap. Also, some in the thread have mentioned 'SM inside concentric circles' as the descriptive text for the mfgr logo.

Look VERY closely at the logo and you should find ONE complete outer circle with a large 'C' inside it both surrounding the 'SM' characters. I believe this was a stylized form of making 'SMC' for Stant Manufacturing Corporation...

[Michael F.]

Re: 1963 Corvette Gas Cap Info Please!

Michael, I believe they are talking about the gas tank cap and not the filler door.
David, I have always been into the 63 caps no matter where they are on the car. Personally I have never seen but one gas cap-one design on all 63's.
A late 63 I once owned was #19426 (easy to remember as 426 was my Mom's house #.) It had the same gas cap as my 9900 plus 63. JD

Thanks, John. I guess my speed reading is a bit weak.

[Stuart F.]

Re: 1963 Corvette Gas Cap Info Please!

Looks just like mine, except mine looks more mottled on the bottom from use so the logo is not as clear. Did we accomplish anything about the extent of use of this cap regarding s/n cutoff dates? Mine was on the car on delivery in August 1963.

Stu Fox

[Jim B.]

Re: 1963 Corvette Gas Cap Info Please!

A couple anomalies as far as the Judging Guide goes...1) with regard to the first design, it speaks of a "flanged" hole on the underside. What exactly is "flanged" on this hole? 2) the JG also only speaks of the second design cap as having the "SM" with the concentric circles. It would appear the first design has this as well, does it not?

[Joe L.]

Re: 1963 Corvette Gas Cap Info Please!

A couple anomalies as far as the Judging Guide goes...1) with regard to the first design, it speaks of a "flanged" hole on the underside. What exactly is "flanged" on this hole? 2) the JG also only speaks of the second design cap as having the "SM" with the concentric circles. It would appear the first design has this as well, does it not?

Jim------


You've got me. However, by any stretch of the imagination I don't think the term "flanged" could be used to describe the hole on the underside of the 1st design cap. All it is is a plain old hole. Period.

The 2nd design cap MIGHT be described as having a "flanged" hole. That's because a "flange" of the internal pressure vacuum valve passes through the hole and is rolled over to affix the valve to the cap. This configuration might be described as "flanged" although it does not precisely describe the configuration.

[Stuart F.]

Re: 1963 Corvette Gas Cap Info Please!

It seems by the information and testimony presented in this Thread that the descriptions in the JG indeed should be massaged on this area, including the cutoff date, logo and appearance. The method of securing the relief/check valve assembly is either a rolled or peened over hollow rivet - not a flange. Several of us have late s/n 63's with the plain hole cap, and the SMC logo appears on both early and late designs.

Stu Fox

[Chuck W.]

Re: 1963 Corvette Gas Cap Info Please!

Jim------


You've got me. However, by any stretch of the imagination I don't think the term "flanged" could be used to describe the hole on the underside of the 1st design cap. All it is is a plain old hole. Period.

The 2nd design cap MIGHT be described as having a "flanged" hole. That's because a "flange" of the internal pressure vacuum valve passes through the hole and is rolled over to affix the valve to the cap. This configuration might be described as "flanged" although it does not precisely describe the configuration.

"Flanged" holes in the stamping business often refers to punched holes vs. drilled holes. Punching produced a slight "flange" of deformed perimeter metal around the circumference of the outside edge.

[Rick A.]

Re: 1963 Corvette Gas Cap Info Please!

and, as was mentioned, it is NOT two concentric circles around the SM - it is a single circle around the SM and the C is really the second "semi-circle" - it is NOT a complete circle

[Timothy B.]

Re: 1963 Corvette Gas Cap Info Please!

Rick,

I need one of those caps for my 63. When you bring your Z close to Harford I am going to put some gas in it.