ok so i am in the process of converting from tpi to carb. When the car goes back together, it will have a zz4 crate motor, thumpr cam, and and edelbrock scorpion intake. I plan on fueling with a proform 750cfm mech secondary carb. I already have ordered and recieved an edelbrock 110gph pump that requires no regulator. My question is ( and i searched so dont bust ***** about this already being awnsered) will this pump suck fuel from the tank if i leave the tpi pump, fuel filter, pickup and lines connected. I know someone out there knows for sure if it will work or not for sure or if its at least worth a shot to use this set-up. Thanks. Joe.

 

no. you will have to either pull the tpi pump out and installa pickup screen and mod the tubes or by an intank pump and install it. why are you going to install a new pump. is the one on there going out. you can install a return style regulator and just use the one in the tank.

 

so i cant run a mechanical pump at all? why not? the mechanical pump must work. i just need to know what else i have to modify for it to work properly. when i disconnected the lines under the hood, fuel flowed through the line without restriction and the pump is still in place.

 

yes a mechanical pump will work but it will starve the engine if you do not remove the the old pump in the tank. you cannot suck thru another pump. you can hook it up and try but you will run into starvation.

 

Why?

The fuel might siphon out of the tank with the electric still in the tank, but that doesn't mean it will flow enough to supply the carb if the electric isn't operating. Either get/keep the electric running and use a return-style pressure regulator, or drop the tank and pull the in-tank electric.

What are the spec on the Thumper cam? Most likely it'll be a downgrade vs. the ZZ4 roller cam.

 

the thumpr is bigger and definatly with 1.6 rockers. Picked up 54hp with the cam swap

i thought ive read about living the stock pump hooked up and running the mechanical pump in the block will cut the pressure down as well as fuel the motor correctly. Any truth to this? if so, what do i do with the return line?

Also, if i take my pick up out of the tank, and modify it as shown in the sticky, will my sender still work? is that wire seperatly of the pump?