I am looking into swapping a carbureted 350 into an 87 Formula that originally had an L-98 but now has no motor. Will a stock replacement mechanical fuel pump for an L-69 be strong enought o pull fuel through the dead mechanical pump? Will I have to drop out the tank and remove the in-tank electric pump? I don't want ot do all that extra work. Would a Holley or edelbrock pump work better? TIA.

 

MCM,

I'm suspecting that you will have some restriction there, but it might not be enough to inhibit flow significantly. It's worth a try, and if you starve it, you'll have to remove the pump (or run it with the ignition circuit and provide a regulator). You might get by without removing it, so it's probably worth the effort.

 

It'll choke you, unless it's very mild motor. Personal experience.

A better way to go would be to continue to use the electrical pump but put a Mallory 3-port regulator on it to knock it down to 6 PSI. The mallory regulator is capable of handling this wide pressure drop.

If you want a really weird but functional solution then leave the pump in (non-running), install a low pressure electrical pump back by the tank (Carter 5 PSI street pump) AND a mechanical pump on the block to put the final pressure regulation on it and shove it up to the carb. Sounds weird but it works like a charm for overcoming the restriction of leaving the dead pump in the tank.

 

i have done this to several vehicles and have never run into a problem. the only ones i did it to were throttle bodies, but the pump for the tpi is the same. never experience starvation; but then again, i don't drive over 100 too much anymore. just make sure your pump is in good condition.