I picked up a Mallory Comp 250 fuel pump used. The 2004 Mallory catalog shows an inlet, outlet, and a 'bypass', and in the photo shows AN style fittings threaded into the pump on all three ports. On my pump the 'bypass' appears to have a plug of some type. If I pull the plug, can I use the port as a bypass? Or do I have an earlier pump? It looks relatively new.

The other thing I was wondering is, I'd like to set up a return line to the fuel cell. Should I set up the return line at the 'bypass' on the pump, or should I plumb two full fuel lines along the frame, and start the return line at the regulator using a three port regulator (two ports for primary and secondary fuel bowl, and third for return).

Also on the fuel cell, do you plump the return line into the top, or use one of the two fittings in the trap at the bottom? I'd think you'd want to keep the fuel all on the same plane, as low as possible, so the pump doesn't have to push the fuel up to the top of the cell.

Thanks.

Sean, the earlier pumps had the bypass plug on the bottom. The later pumps have the bypass on the side between the input and output fittings.

Yes, you can/should remove the plug and run an 8an bypass line directly up to the TOP of the fuel cell. DO NOT use one of the bottom fittings on the Cell. Forget running a return style regulator, there a pain and unnecessary.

Run 8an fuel line from the pump to the regulator and from the regulator to the carb fuel log which should also be 8an. Go with a Holley big-port (dead head style) regulator it out flows just about any other dead head style.

Sean, I just emailed the Comp 250's instructions to you. They explain what to do with the port you are aking about. To summarize it, they recommend a return style regulator. If you use a "dead-head" style regulator (no return), you need to connect a bypass hose from the pump bypass port back to the tank. You have to run a regulator with this pump as output is about 15psi.

Tom

Here are some pics of mine. Make sure you put a ground wire from the metal fill hole on the fuel cell to a ground source.

http://home.swbell.net/kenladd/fuel_cell.jpg
http://home.swbell.net/kenladd/apd.jpg

Wow! Awful fancy, dude. Let's see the rest of the car! :D

http://home.swbell.net/kenladd/launchpicture4.bmp

That almost looks like another guy who used to post here. :eek: Nice straight launch!!

Thanks for the advice, guys. I think I can manage it from here... graemlins/thumbsup.gif

That a Ford-style distributor cap there, Gateway?

That almost looks like another guy who used to post here. Nice straight launch!! Hmmm, Imagine that, another red Chevelle on this site. Bet mine is faster! :cool:



That a Ford-style distributor cap there, Gateway? Nope, it’s a Msd Pro Billet style! ;)

actually it is better to run a bypass regulator and have a return line than run the bypass in the pump, that way the pump can run at free flow and never get congested, the bypass in the pump isn't all that good, also using the regulator as a bypass also lets your fuel circulate and lets it stay cooler since it isnt'staying stuck up at the front. another thing is the with the bypass in the pump, the fuel not being pumped still stays in the line, only the incoming fuel going into the pump gets bypassed and goes back to the tank, but if you already have a dead head and don't want to run the return line which needs to be the same size as the supply line than use the bypass in the pump