C1 and C2 Fuel Pumps

[Christopher R.]

My 4656 clone pump leaks every year. I've now ruined it by overtightening the cap screws. It's not rebuildable. That's OK, I don't want to rebuild it. It's a safety issue with me now. Originality be damned.

Can somebody give a rundown on C1 and C2 fuel pumps? Including options for incorrect but currently available replacements. I wish to replace the 4656 fuel pump on my '62, and I want to know what my options are.

I know you can make 4656's into 4657's and vice versa. I know other models interchange if you turn the bottoms around. But not sure which ones.

1. What's the Chevy and/or Delco part number for the pump the Corvette vendors are selling today as incorrect but close? Is it the crimped style? Or, is it the rebuildable type with the 10 or so cap screws holding it together? Are the inlet and outlet in the same positions as the 4656 pump?

2. What's the 6415616 pump? Greenwood (on EBay now) advertises it as a 59-65 pump. Is this discontinued?

3. What's the 40083 pump? Is this the crimp style pump?

[William C.]

Re: C1 and C2 Fuel Pumps

40083 is a special pump for the high performance smallblocks, and has the inlet and outlet 180 degrees from one another rather than at an angle like the 4656 and 4657 had. There are other variations in the top casting also. The top casting for the 4656 is very somilar to and interchangable with the tio castings fro any AC pump from a smallblock v-8 pre 1966, in other words, any original 283 pump can donate it's top for your unit as long as the part that mates to the bottom of the diaphram is usable.