I swapped my LG4 for an L31 which I converted to carbed. This means I have to swap my mechanical fuel pump for an electric one. The pump I purchased is a Professional Products Powerflow 10700. The problem is that the instructions say to mount it with the outlet facing up at a 45 degree angle and the only place to do that is in the engine bay next to where the old mechanical pump was. Most people seem to mount their fuel pumps in the back of the car, will mounting it in the front be OK?

Also there are two lines going into the old mechanical pump, but only one line coming out, what is the second line?

 

Second line is the return line back to the tank. It was a vapor lock prevention thing, it didn't function in the same capacity as a return line on an EFI engine. You don't have to use it if you don't want to. Plenty of people have put on aftermarket mechanical pumps with no return line in place of the stock fuel pump.

Your 86 SHOULD have a low-pressure in-tank electric pump already (all 85-up carb'ed Camaros did). I can't say I have ever used an electric pump up under the hood, personally, but it should work just fine in combination with the factory low pressure in-tank pump.

I checked out that pump, since I wasn't familiar with it, and the GPH rating is not exactly "high performance" but should be more than adequate to keep up with an LG4. With an L31.... I'm not so sure. Guess it's worth a shot. Note the factory fuel feed line is 3/8" and that pump only comes with fittings for smaller 5/16" line.

 

Thanks for the response!

It should work out ok, the positioning means I can tap the existing fuel hoses into the new fuel pump and its not a high performance engine so flow rate shouldn't be an issue.

 

That's because it's the proper place to mount them, Most all electric pumps are designed to push the fuel from the back to the front, Not suck the fuel from the back to the front.

You'd be way ahead (easier/less trouble) to add a return style pressure regulator under the hood and run the stock in tank pump.

Good luck with that cheap pump......

 

That in tank pump isn't designed to work n it's own. The original fuel pump was in the front of the car and from a physics standpoint it shouldn't matter where you put it horizontally.

 

You'll burn the electric pump up mounting it under the hood. Unless you are POSITIVE that it is meant to be used as a "puller" pump.

Many people have just put a higher quality in take pump in and been fine.

I run a Holley blue pump mounted on the tank.

best of luck.

 

IF you've got the in-tank helper pump AND it's in working condition, you'll be fine with the little electric mounted up front. I've not seen an 85 or 86 WITH the helper pump but I've only examined one or two.

Retaining the return is best. Note how close the fuel lines run to the exhaust on the right side. Allowing fuel to flow continuously will keep it from overheating in the lines and boiling out of the carburetor. If you add headers this situation can even worsen.

I run my fuel through a non-functioning mech pump on the block in order to retain the return flow. Been working fine for many years. I've also wrapped my fuel lines along the exhaust run with insulation. I don't like it when fuel boils out and my car runs like crap, if at all.

 

Well I'm positive that the pump has to be mounted at 45 degrees with the outlet facing up and that the only place to do that is under the hood.