4657 fuel pumps

[Mike E.]

After checking through the archives, I still have a few questions about these. The pictures attached show a small font 4657 stamping, on the upper side of the flange, a larger font stamping (this one with an A suffix), and two different types of boss configuration on the screw holes.
I'm going to make some conclusions, and ask you all to shoot holes in them if you like. Conclusions:
1) the small font on with the casting line is the earliest of the 4657 fuel pumps. 1963? This also has the strictly circular screw hole bosses as show in the picture. Both of these are like the 58-62 correct 4656 pumps, except of course, for the 4657 stamping.
2) the large font 4657 stamping followed. It was along the lower flange, and there was no casting/parting line on the flange by the stamping. This change also included the rectangular bosses interspersed with the circular bosses as shown in the picture.
Questions:
1) the pump shown, with the 4657A stamping, has me wondering. It is configured like the second-type 4657, but the lone "A" doesn't fit with anything I've found in the archives. Most had a two-letter suffix. Is the 4657A the first successor to the large 4657?
2) Would the sequence be small 4657, then large 4657, then large 4657A, then large 4657's with two-letter suffix? I checked the new 63-64 JG, and none of this was addressed.
Thanks for your input!

[Mike E.]

Re: 4657 fuel pumps

No input in 24 hours. Nobody knows, or nobody cares? '63 guys, where are you?

[Harry S.]

Re: 4657 fuel pumps

Mike, as far as I know in 63 only 4657's without a suffex were used. And you could have them with and without the frogpad.

[David L.]

Re: 4657 fuel pumps

Mike,

In the hole just above the threaded outlet there should be a 2-digit casting year surrounded by 1 to 12 radial hash mark (like a clock). If the pump is original (not rebuilt by a rebuilder) this will tell you the month and year the bottom part was made.

Dave

[Mike E.]

Re: 4657 fuel pumps

David,
I was hoping you would jump in. I'm aware that the date is there-I'm guessing the large 4657 and 4657A I have are rebuilt. What can you tell me about the 4657A vs. large 4657?

[David L.]

Re: 4657 fuel pumps

Mike,

I have never seen a 4657 AC fuel pump with just one letter ("4657A", in your case). I have no explanation other than a possible stamping error at the AC plant. I have had many used original as well as NOS AC 4657 fuel pumps over the decades but they are long gone. I don't remember ever having a 4657 pump with small digits (about 1/8" in height as best as I can remember). I believe that the early pumps stamped "4657" do have the small digits as well as a seam on the flange.

Dave

[David L.]

Re: 4657 fuel pumps

Mike,

About a year ago I found a very nice original AC 40394 fuel pump at a swap meet in Connecticut for $5 stamped "40394" in small 1/8" high digits on the flange edge as well a "66" casting year with one hash mark (as best as I can remember for January 1966) on the back side (surface that mounts on the block). Apparently the 40394 pump is very rare. It was original equipment on 1966 Nova models w/327 SHP (L79). There was a seam on the flange. I tried posting a photo from my imgur account but for some reason I could not so I added the photo on the NCRS site. Refer to the link below for more photos and description of the 40394 on my Oct. 23, 2012, post.

Dave

https://www.forums.ncrs.org/showthre...0394+fuel+pump