Go with 80gph or 120gph mech. pump...?

[Beatnik]

Ok guys. I'm about to change up my 340 significantly to the below specs and have 2 pumps available to me to replace my stock OEM pump. Keep in mind stock tank/lines etc.
-Summit 80gph
-Carter M6270 120gph (strip version)

Thinking the Summit may not be enough and the Carter too much. Probably the street version 120gph M6902 Carter would be best?

Whats a factory pump gph rating anyway..?

Combo will soon be:
340 bored .030 over
11.1 compression domed pistons
Ported X heads w/ 5 angle valve job etc...
Purple 292/.508 cam
Air - Gap intake w/ fresh 650 double pumper
MSD billet dist. w/ Mallory 6AL ignition

 

[scamp 408]

To run the strip pump you are gonna need a regulator .Too much pressure. Those pumps pressure wise # shown are rated at a higher rpm .Idle it may exceed 10-12psi .Ask me how I know.

 

[fishy68]

Beatnik I don't know specific fuel consumption numbers but after reading "Tuning To Win" by Don Gould at FBO systems I don't think 120gph is Too much at all for your build. The carb. only uses what it needs anyway and it's not good at all to run lean. I don't like the high pressure units for the street either. Had problems with flooding at idle like Scamp mentioned. The street version is probably best unless you run a good regulator. And I don't mean one of those cheap junk Holley $15 units. IMHO

 

[Beatnik]

Thanks guys. I agree with both of you. I got the Summit 80gph pump so I'm gonna use it. Gotta be better than my OEM pump anyway. If it keeps up great, but after I tune my carb and get my timing all squared away if it's not keeping up I'll go w/ a street 120gph probably.

I actually talked to Dan Gould yesterday and we had an interesting conversation regarding my car and it's lackluster performance and ability to rev only to 5500. After I make a few adjustments and get the right coil and ballast for my FBO ecu and dist. I think it unveil the other weaknesses in my combo (fuel pump among one).