66 L79 fuel pump - Will the work?

[Donald H.]

The TIM & JG says the correct fuel pump is the 6440083 with the stamped steel/cad dichromate finished bottom.

Long Island Corvette sells rebuilt 6440083 pumps that appear correct except they have the cast bottom, which may be correct for 64-65.

I also see used replacement pumps on ebay that have the stamped dichromate bottom. They do not have AC stamping on the top but appear to be exact copies, maybe Airtex or later Delco replacement.

My question is, if I buy one from LIC with the cast base, can I use the base off one of the replacements with the dichromate base and end up with a pump that will pass judging.

Thanks,

Don

[Page C.]

Re: 66 L79 fuel pump - Will the work?

Don,
Most of the repro 6440083 fuel pumps do not have the 2 gussets between the upper pump body and upper stem. This is easily seen during judging. Do a search and I'm sure you will find photos of the correct pump with the gussets.
Page

[Donald H.]

Re: 66 L79 fuel pump - Will the work?

Don,
Most of the repro 6440083 fuel pumps do not have the 2 gussets between the upper pump body and upper stem. This is easily seen during judging. Do a search and I'm sure you will find photos of the correct pump with the gussets.
Page

Thanks, I'll look for pictures. But I though I was looking at a real 40083, or at least that is how LIC advertises it. But it has the cast base with AC on it instead of the stamped steel base. I was only looking at a used repro on EBay to get the dichromate plated stamped steel base.

Are you saying the ones that LIC advertise as rebuilt AC 40083s are repros?

[Page C.]

Re: 66 L79 fuel pump - Will the work?

Don,
There was also a great 8 page article in Vol 37 #1 Summer 2010 on rebuilding the 6440083 pump showing the gussets in the top of the pump that are missing in most repro pumps.
Page

[Donald H.]

Re: 66 L79 fuel pump - Will the work?

Page,

I found the article and see the gussets that you mentioned.

Thanks,

[Joe C.]

Re: 66 L79 fuel pump - Will the work?

The other major characteristic missing from modern reproductions which advertise and sport the "AC" logo, is the double stepped boss for the pivot pin. Minor characteristics also missing from these are the "S" body and cover attaching screws, magnesium pump body, and special pivot pin which is deformed to retain and does not use an "E" clip.

FYI: The pump shown in the article is an early service replacement pump. It differs from a production pump in that it has an alpha code in addition to the stamped "6440083". There is still much speculation on the meaning of that alpha code. The jury is still out on it.

[Donald H.]

Re: 66 L79 fuel pump - Will the work?

The other major characteristic missing from modern reproductions which advertise and sport the "AC" logo, is the double stepped boss for the pivot pin. Minor characteristics also missing from these are the "S" body and cover attaching screws, magnesium pump body, and special pivot pin which is deformed to retain and does not use an "E" clip.

FYI: The pump shown in the article is an early service replacement pump. It differs from a production pump in that it has an alpha code in addition to the stamped "6440083". There is still much speculation on the meaning of that alpha code. The jury is still out on it.

I found your article. There is one on Ebay now from Goathill that has the double stepped boss and the extra reinforcements at the base of the plunger rod housing and stamped 40083 on the flange. At $450, that is a bit more than I want to pay, plus it has the case base and not the stamped steel base. Is the cast base just the sign of an earlier pump?

http://www.ebay.com/itm/ORIGINAL-1964-1966-Corvette-Hi-Po-AC-40083-Rebuilt-Fuel-Pump-/300646358106?pt=Motors_Car_Truck_Parts_Accessories&hash=item45ffeb5c5a&vxp=mtr

[Joe C.]

Re: 66 L79 fuel pump - Will the work?

That appears to be a production pump. The pivot pin is home-made, and a decent attempt, although the deformed end can't be seen. Aside from the head being too large and too thin, the pin is incomplete in one very important aspect.

[Donald H.]

Re: 66 L79 fuel pump - Will the work?

That appears to be a production pump. The pivot pin is home-made, and a decent attempt, although the deformed end can't be seen. Aside from the head being too large and too thin, the pin is incomplete in one very important aspect.

What about the cast base versus the stamped steel as in your article?

[Joe C.]

Re: 66 L79 fuel pump - Will the work?

Either is typical production. Others may have more details on timeline.

[David L.]

Re: 66 L79 fuel pump - Will the work?

The 1966 Chevy II/Nova w/SHP 327 engine, 350 H.P. (L79 option) used a similar AC fuel pump that was stamped "40394" on the flange. The angle between the inlet and the outlet is 108 degrees. The angle between the inlet and outlet on a "40083" pump is 180 degrees.

Both pumps have "PT 5623145" and the month & year cast on the flange part that mounts on the engine. The original pumps that I have had also had a "5A" casting (possible molding number). You can not see these casting numbers when the pump is mounted on an engine.

Enclosed are 4 photos of a 1966 Nova L79 pump stamped "40394" on the edge of the flange with the "PT 5623145" casting as well as a "66" with one radial line segment (January 1966) on the back side. I just bought the pump last Sunday at a swap meet in Stafford Springs, CT, for $5.00. The "40394" pump is AC # 6440394 which is GM # 6416387.

The "40083" pump is AC # 6440083 which is GM # 6415325.

Dave

[William C.]

Re: 66 L79 fuel pump - Will the work?

Also of note is the original 40083 pumps were made with a magnesium cast main body, not always true of the later ones, and easily detected by color differences.

[Joe C.]

Re: 66 L79 fuel pump - Will the work?

Also of note is the original 40083 pumps were made with a magnesium cast main body, not always true of the later ones, and easily detected by color differences.

Bill,
See post #6.

[Alan D.]

Re: 66 L79 fuel pump - Will the work?

So here is an example from a Mar64 car;

[David L.]

Re: 66 L79 fuel pump - Will the work?

Alan,

Does your pump from a March 1964 car have the casting number "PT 5623145", a 2-digit year date code with anywhere from 1 to 12 radial "hash" marks around it, and a "5A" (possible molding number) or something similar on the back side where the pump mounts to the engine block?

Dave