Electric Vs. Mechanical Fuel Pump? A Novice Question:

I replaced my engine with a basic 350 crate engine. The previous owner of my car had it set up with an old (and improperly installed) electric fuel pump, so I was about to replace that and the old fuel line. This got me thinking about going back to a mech. fuel pump.

Any reason in a mild engine not to go back to a mechanical pump since I'm redoing everything anyway?

 

I'd go mechanical if possible.

If you do go electric use a Carter and stay away from Holleys.

 

Make sure its not a newer crate motor , the one I did for a friend didnt have the lobe on the cam for the mechanical pump but had the place to mount a mech one. Drove me crazy! I guess they think we all are using fuel injection.

 

I would go with mechanical if at all possible

 

Thanks guys-

It's the basic "Targetmaster" (or whatever they call it) GM Goodwrench engine for 1970-mid-80's products, so it should have the lobe to drive the pump.

I'm gonna head to the parts store (no work today- its my Saturday)to get a mech pump and pushrod. Any brand I want to avoid? Or is the basic Airtex or whatever they're selling OK?

 

Something you might be overlooking on that olds, is that the stock quadrajet is more than big enough to feed the engine, and works fine with a stock mechanical pump. Just because you have dual quads, does not mean the engine is necessarily using more fuel! if you're making well over 450 hp then you might need to step up to an electric pump, or a high perf mechanical pump.

 

On the Olds, you are also effectively doubling your float bowl/reserve capacity so the stock mechanical should be more than adequate unless you are legitimately pushing more than 550HP. With the dual quads your fuel pump won't be deadheading near as much thereby possibly extending the life of your fuel pump.This is similar to putting another tank on your 5hp 10cfm 110V Craftsman compressor, it gives you more air available to use and the pump won't have to work as much to satisfy the demand because of the additional storage. The pump will run longer but it will also have a longer off time before the demand to switch on again.

 

Personally, I would run an electric pump instead of a mechanical one for several reasons.
-An electric pump is easier to change
-The electric pumps make a little "whirrrrr" noise when they run, so you know if it is working or not
-My cars will often sit for a week to a couple months without being fired, which makes that first start a nightmare. The mechanical pump needs to crank the motor over dry until fuel pressure is built up. With the electric, you just turn the key on, pump comes on and delivers fresh fuel and full pressure, then fire it.
-Neither myself or any of my friends have had any trouble with Holley pumps. We run a Mallory in our race car and it performs very well.

 

Well, turns out there is not room for the mech pump after all, so I'm back to electric.

Does anyone have a part#/source for the Ford-type inertia switch? That seems like a desireable safety feature.

 

Carter #4070 super reliable and can handle the volume.

 

quote=wingnutz : I have a Dual quad on a 455 Olds engine and would like to run a mechanical pump... however I don't think they can push the volume needed for the dual quad...!

Squirrel's right on the dual quad volume issue.

Either of the dual quads will be pulling about half the air/fuel mix the single quad did due to the engine can only pull so much air.
Less air through the venturi's = less fuel pulled due to the venturi pressure differential.



What is the greatest mechanical fuel pump volume you can buy for a GM car...??? (Specifically a BBO 455??)

With a GM engne, you may be able to get a Chevy high volume fuel pump and put the pump section on the Olds base.
Then you'd have a high volume Olds pump.

I believe Carter's are the pumps to use for this trick.

Carter's not going to make a different pump bolt pattern for different engines when all that's needed is a different base.


Or do I need to stick with an electrical pump?

Maybe . . . if you can put together your own high volume mechanical pump the question may be moot....

 

More than likely you can walk into the Ford parts department and ask for any inertia switch.
If they are different, the ones in the 89 Rangers were under dash and may be easier to mount.


Along those same lines, Stewart-Warner makes an oil pressure safety switch that will cut power to the fuel pump when the oil pressure goes to zero - or very low.

You'll need a primer ****on to byp*** it if you want to fill the carb float bowls without cranking the engine.

NAPA sells a nice two terminal switch that looks like the 49-50 Ford - & earlier - starter ****ons.

Got a pic if needed.

 

For the money right now you can't beat the 4070 Carter.

 

there's more info on wiring oil pressure cutoff switches in this thread

http://www.jalopyjournal.com/forum/showthread.php?t=127665

.

 

Definitely go the Carter. Also be sure to run a regulator, especially if your running an aftermarket perf carb. Holley's don't like much more than 5psi. A regulator will keep it from flooding and extend needle and seat life.

Mallory makes really nice regultors but they're pricey. The holley regulators are cheap and small and work pretty well, unlike their pumps.

 

or you could get a 15-20 year old holley pump, they still work pretty good!