i was wondering if anyone had any suggestions about a fuel pump situation in switeching from a mpfi system to a carb system.
origionaly i thought about just putting in a fuel pressure regulator but now am thinking about droping the tank and just changing the pump completly. any suggestions would be great thanks

 

Are you converting the V6 to carb, or going with a carb'd V8?

 

i got a carbed v8 to put in it wit a 600 cfm holly carb

 

Personally, I think an electric back by or in the tank, pushing to a mechanical on the engine, regulated as necessary (return-style reg if you use an in-tank electric) is the ideal set-up.

The stock V6 pump won't support a whole lot of power.

 

so could i use the stock v6 eletric pump thats in the tank with a mechanical one on the block to regulate and ill be ok?

 

I doubt you are that lucky,........ I'm quite sure that the MPFI fuel pump puts out much more pressure than the carb will require. I have bever tried a setup like that - and probably never will !

I've done a couple V6 MPFI to V8 carb swaps in the past and I'm in the middle of one right now. I just pulled the fuel tank and replaced it with one that has a Carb Fuel Tank Pick-up yesterday afternoon. There will be 1 Fuel pump that's block mounted - like 90% of Small Block Chevy Carb engines. If you plan to use a block mounted mech. pump than remember that the fuel lines will need to be re-roughted to the drivers side of the engine bay.

I have been told that simply removing the MPFI pump from the original pick-up would allow the MPFI Pick-up to be re-used. I guess the pump restricts the fuel flow too much if left installed ??? I'm also guessing that the pick-up line may need to be lengthened to sit at the bottom of the tank ?? I have always removed/replaced the entire pick-up assemebly to keep things simple.

Some people prefer a single Electric pump,....... Be sure it's made for a Carb and install it in the front or Back based on the directions with the pump.

Hope that helps in some way !!

 

The pump will only generate the pressure that the resistance to flow will allow. If you use a return-style regulator, it will put out 4-7 psi after you adjust the regulator to a carb-friendly pressure.

The issue is volume. The V6 pump will put out more volume at a lower pressure than it does at MPFI pressure, but it still probably won't be adequate for a good-running V8.

 

i am thinking about putting an intank eletric fuel pump but will that be able to plug in the same spot as the old one and still work or will it be a problem because of the computer and relays?

 

Definitely need the relays. I've gotten mixed messages about the fuel pump running without doing anything, or not running unless rewired. Mine didn't have the electric pump, so my direct experience isn't much help.

 

but the simple solution would be either a mechanical instead or run the electrical to the igniton switch and just bypass the relays and cpu?

 

Running the electrical power through an oil pressure switch is a good idea for safety's sake.

Mechanical is pretty simple, and that's why the sticky about converting the pick-up from in-tank electrical pump to simple pick-up exists.