?? regarding my '67 fuel pump

[Barbara S.]

I just removed my fuel pump from my '67 coupe. I'm about to start tackling my engine restoration. It sure looks original, but after 38 years, who knows?

Here's what I have. On the sides, in raised letters is reads AC. The only numbers that really appear to be a part number, it reads: 281R40988.

Can someone tell me what I got??

Thanks!
Tony

[Gary S.]

Re: ?? regarding my '67 fuel pump

Tony, I would suggest that you visit the NCRS store and buy a 67 Judging Guide. While I don't know the answer to your questions, the JG will have all of those numbers available for you. You will find that the JG is something that you keep right along side your AIM, Assembly Instruction Manual for reference. Both are extremely valuable and chock full of great information.

Gary

[Joe R.]

Re: ?? regarding my '67 fuel pump

Hi Tony:

The 67 small block fuel pump had "AC" cast into the side of the upper aluminum housing, with a steel gold-cadmium plated lower body that was crimped over the lip of the aluminum upper housing. The crimped-on lower housing meant that the pump could not be rebuilt using standard tools.

The fuel inlet used a screw-in 90 degree elbow fitting, as opposed to the welded pipe elbow on many service replacements.

The TIM&JG says the part number was 6440433. I believe that some or all of this part number (possibly just 40433) was stamped into the flange of the aluminum casting.

If any list members can clarify exactly what numbers should be stamped on the flange, I would like to know.

[Barbara S.]

Re: ?? regarding my '67 fuel pump

Thanks Joe. I should have added that the engine is a 327/300 hp A/C car.

Tony

[Joe L.]

Re: ?? regarding my '67 fuel pump

Tony-----

Well, what you've got is an AC type 40988 fuel pump. The only application that I can find for this pump is some 1973 passenger cars with small block V-8. It was not originally used on a Corvette and certainly not a 1967 Corvette. Keep in mind, though, that most small block fuel pumps are functionally interchangeable. The differeences often lie in the configuration of the inlet and outlet fuel fittings, although there may be other differences, as well.

Apparently, the type 40988 will function just fine for a 1967 Corvette. However, it's not the correct pump for such an application. The correct pump is an AC type 40433. That is a VERY difficult pump to find. However, the SERVICE replacement fuel pump for your application for the last 35 years, or so, has been the AC type 40503 also known as GM #6416712. That pump is still available from GM for a current list price of $37.53.

[Joe R.]

Re: ?? regarding my '67 fuel pump

Hi Joe:

The TIM&JG says the 67 small block fuel pump is part number 6440433. Would the number stamped on the fuel pump flange be 4140433 (presumably the AC part number)?

[Joe L.]

Re: ?? regarding my '67 fuel pump

Joe-----

The PRODUCTION 1967 small block fuel pump was AC type 40433 or GM part number 6440433. The 6440433 was a PRODUCTION-only part number and was never available in SERVICE. The numbers stamped on the pump flange include the AC type number + certain other coded information.

The original PRODUCTION pump, AC type 40433, was once available in SERVICE under GM part number 6416509 or AC 40433. However, it was discontinued from SERVICE in February, 1967 and replaced by the AC type 40503 aka GM #6416712 which remains available to this day.

Original PRODUCTION and SERVICE examples of the 40433 will have that number stamped on the flange. They will also have the "AC" cast on the upper aluminum casting of the pump. Later SERVICE examples of the 40503 will have that number stamped on the flange and will also have the "AC" on the cast aluminum upper body of the pump. Examples of the 40503 available in SERVICE for the last 15+ years may or may not have the number stamped on the pump flange and will not have the "AC" logo on the casting. That's because AC has not manufactured a mechanical fuel pump in about 20 years; all are "outsourced". Current examples usually have laser printing on the aluminum casting which includes AC type number and/or other information.

So, what's the difference between the 40433 and the 40503? Well, I think that it relates to the inlet fitting. I believe that the 40433 uses a threaded inlet fitting whereas the 40503 uses a nipple-type inlet fitting.

[Barbara S.]

Re: ?? regarding my '67 fuel pump

Joe. If the 40433 was discountinued in Feb '67,then it was discountinued before my car was built in June, '67. What would you suggest that I choose for my fuel pump then? The AC type 40503?

Tony

[Joe R.]

Re: ?? regarding my '67 fuel pump

Thanks Joe. I was interested in the correct stamping for the flange of the original GM 6440433 because I somehow had the impression it should read 40433. I have a remanufactured/reproduction pump that I got from Goat Hill Classics that appears to be visually identical to the original design, but the stamping on the flange reads 4140433. I'm not sure whether the judges look at the number stamping, but if they do I would like to be assured that 4140433 is correct. I'm curious as to whether 4140433 is the complete AC part number.

[Joe L.]

Re: ?? regarding my '67 fuel pump

Tony-----

The 40433 was discontinued from SERVICE in February, 1967. That does not mean, however, that it was necessarily discontinued from PRODUCTION at approximately the same time or, even, ever as far as the 1967 model year goes. My opinion would be that the 40433 was very likely discontinued from PRODUCTION sometime during the 1967 model year and replaced by the 40503. Just when that occurred, if it did occur, I do not know. If the JG says that the 40433 is the only pump considered correct for a 1967 small block, then that's the one you'll need (assuming that "correctness" for judging standards is your goal).

I should point out here that the 1967 AIM shows only the 40433 with no supercession. However, we don't necessarily know if the page of the AIM covering the fuel pump that's in the copies we have today was the same one that was effective as of the last day of PRODUCTION. It's very possible that a revision was made, the page updated, but that page never got into the "original" set that was the genesis of the copies we have today.

[Joe L.]

Re: ?? regarding my '67 fuel pump

Joe-----

No, it's not. The complete GM part number for the pump was 6440433. The AC type number was 40433 (which is the last 5 digits of the GM part number). The SERVICE part number for the pump was GM #6416509 (box contains a pump of AC type 40433 + 1 gasket). The "41" prefix has some other meaning and is not related to the part number, at all. It's just part of a code which includes the AC type number.

I used to know how to decode these things, but I forgot it. Paul Baker (of Goat Hill) knows how to decode them but, reportedly, he won't share the information with anyone.

[Joe R.]

Re: ?? regarding my '67 fuel pump

Thanks Joe. I guess I'll just have to trust that Goat Hill is correct in using the 4140433 stamping. I find it interesting that the TIM&JG states that the fuel pump was GM part number 6440433, but fails to say what number should actually be stamped on the fuel pump flange. I think it is generally understood that the number stamped on fuel pump flange is *not* simply a duplicate the GM part number.

[Page C.]

Re: ?? regarding my '67 fuel pump

HI Guys,
I have one fuel pump that I think is original to the small block 1967 Corvettes. It's stamped CG40433 on the lower rear flange.
Hope this helps.
Page Campbell

[Barbara S.]

Re: ?? regarding my '67 fuel pump

Thanks again Joe. Your knowledge is exceeded only by your many courtesies.

Tony