Ac 4656 fuel pump

[Gary L.]

Anyone know if this 4656 ac pump is correct for early 59 (Sept build) Vette with dual quads? One at Corvette Central shows to be correct, shows embossed AC on top and bottom shows their part number as 351314. Not sure if the 4656 is stamped on the pump or where the location would be. Would there be a date anywhere?

[Donald H.]

Re: Ac 4656 fuel pump

4656 is either stamped or part of the casting and should appear on the edge. The 4656 is somewhat rare and I believe a very similar AC pump if often restamped as a 4656. I've attached a picture. There are a number of thread if you do a search you will find more info. Just search on 4656 fuel pump. Below is one of the links.

https://www.forums.ncrs.org/showthre...270#post577270

[Mike E.]

Re: Ac 4656 fuel pump

The pictured pump is, in my humble opinion, a restamp.

[Bruce B.]

Re: Ac 4656 fuel pump

According to the experts there should be a parting line on the surface where the number is stamped.

[Tom F.]

Re: Ac 4656 fuel pump

Hello Gary:

The 4656 pump was also used on 1959 Crusader Marine and 1959 to 1967 Owens Yacht 283, 327.

A boat mariner may be also be some other place to find an original AC 4656.

[Gary L.]

Re: Ac 4656 fuel pump

Thanks everyone for your input. I will try to look in archives to see what pump was used for this car.

[Joe M.]

Re: Ac 4656 fuel pump

I purchased a "correct" 4656 from CC last October. It is a 4656, but not 100% correct. It passed NCRS flight judging without deduct. The first two attached photos show what the original, correct 4656 should look like. The last two photos show what I received from CC. Note the top plate is different as shown by 2 yellow arrows and the "4656" stamping is on a smooth surface not across the parting ridge like the original. I believe that any time the fuel pump number is stamped on a smooth surface, it is indicative of a restamp where they ground off the original stamping and the parting ridge. The correct 4656 pump is not easy to find. Restamps are easy to find. Don't purchase a pump until the seller provides you with enough photos of the pump to convince yourself that it is correct or a restamp.

[Joe M.]

Re: Ac 4656 fuel pump

Gary, there won't be a date on the 4656 pump. Later in the 1960s, maybe mid 1960s, the month and date were stamped inside a circular depression next to the inlet or outlet, can't remember which.

[Mike E.]

Re: Ac 4656 fuel pump

Gary, there won't be a date on the 4656 pump. Later in the 1960s, maybe mid 1960s, the month and date were stamped inside a circular depression next to the inlet or outlet, can't remember which.

I have to disagree. The date was cast in the BODY of the 4656 long before 1966. It was inside one of the circular castings along the outer portion of the body, and really is only readable with bright light focused into that area. Problem is bodies can be easily interchanged--tops are where the last four digits of the part number are stamped.

[Tom F.]

Re: Ac 4656 fuel pump

Gary:

I did some additional research in my GM parts catalog. The GM part number that covered 56-to 58 and 59-to 63 was 5621638 stamped 4445-4656 or4663.

The Diaphragm Unit Fuel and Vacuum pump repair Kit that covered the following pumps was 5622175 for AC R-467 (w/4430-4432-4445-466-4657-4662-4663-4665-4701.

[John D.]

Re: Ac 4656 fuel pump

Make sure your fuel pump is rebuild for ethanol. Call Jackson's Old Car Parts at 888-399-7278 for an ethanol/alky kit.
I called then on Valentines day and asked Jackson's if in fact there kits were for ethanol. They insured me that there were.
Now if you are worried about gasket colors then forget it. But if you want to not worry about fuel pump issues then go for it.
For my 63 #4657 pump the kit # is KEM FPA241.

When you are installing the pump go to a good auto store and ask them for some rubber hose for ethanol. JD

[Gary L.]

Re: Ac 4656 fuel pump

Looking for original rebuilt. Must pass ncrs judging for early, sept. Build, 59 vette. Thanks for all of the input. Have a 4663 pump without ac markings and it is causing issues with judging. Some agree and some don't.

[Joe M.]

Re: Ac 4656 fuel pump

The 4656 I purchased from CC in October 2011 passed NCRS judging; zero deduct. CC price was good in my opinion.

[Mike E.]

Re: Ac 4656 fuel pump

Chapter, regional, or national judging?

The 4656 I purchased from CC in October 2011 passed NCRS judging; zero deduct. CC price was good in my opinion.

[Gary L.]

Re: Ac 4656 fuel pump

Dallas last time.