# Electric Fuel Pump vs mechanical on '71 Mach 1 **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** ford\ **Created:** [October 8, 2012, 5:54pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874 "2012-10-08T17:54:35Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![George5060](https://avatars.discourse-cdn.com/v4/letter/g/958977/32.png) [@George5060](https://community.cartalk.com/u/George5060)\ **Post date:** [October 8, 2012, 5:54pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/1 "2012-10-08T17:54:35Z")
I just acquired a '71 Mach 1 and noticed an electric fuel pump wired up in the trunk behind the left wheel well. There is a toggle switch wired to the center console. Is the electric pump the way to go or would the mechanical pump be sufficient for a 800CFM 4 barrel carb? not sure if its working properly as I had some carb problems that I am taking care of as we speak. Also, would I need a pressure regulator for the electric pump? ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [October 8, 2012, 6:06pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/2 "2012-10-08T18:06:54Z")
What kind of engine is in that car to require 800 cfm? That large a carburetor needs a significant fuel pump and the help of some veteran muscle car mechanics to get it set up properly. 800 cfm wouldn’t work well unless the engine was \>7L and operating at near 7000 rpm. ---
**Author:** ![George5060](https://avatars.discourse-cdn.com/v4/letter/g/958977/32.png) [@George5060](https://community.cartalk.com/u/George5060)\ **Post date:** [October 8, 2012, 6:13pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/3 "2012-10-08T18:13:40Z")
it’s a 4781 holley (850cfm) on a 351 Cleveland…What carb do you suggest? ---
**Author:** ![missileman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/missileman/32/1366_2.png) [@missileman](https://community.cartalk.com/u/missileman)\ **Post date:** [October 8, 2012, 6:25pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/4 "2012-10-08T18:25:51Z")
George…a 450 Holley will work just fine for street performance. I would use the electric fuel pump if the pressure is adjustable for the carb that you are using. ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [October 8, 2012, 7:20pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/5 "2012-10-08T19:20:52Z")
Yes, a 450 cfm would be a good match at rpms up to 6,000 on a 351 engine. That 850 will make the engine fall on its face above 1/2 throttle. ---
**Author:** ![oldbodyman](https://avatars.discourse-cdn.com/v4/letter/o/bbce88/32.png) [@oldbodyman](https://community.cartalk.com/u/oldbodyman)\ **Post date:** [October 8, 2012, 9:07pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/6 "2012-10-08T21:07:26Z")
Yes, way to much carb for that. I ran a 850cfm on 383 Mopar. It was great at the track, but not good on the street. I ran a 600cfm on the street motor. I did a lot of work on the motor to run a 850cfm carb. I would keep the electric fuel pump and use a regulator. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [October 8, 2012, 9:35pm UTC](https://community.cartalk.com/t/electric-fuel-pump-vs-mechanical-on-71-mach-1/74874/7 "2012-10-08T21:35:25Z")
The electric pump was probably installed to overcome vapor locking problems in hot weather…Is the mechanical pump still in the fuel delivery circuit or has it been bypassed?