I'm putting together pieces for a TPI swap onto my 85 T/A in 2021. A few years ago I polished up a complete setup that was initially planned to go on my 78 Vette. Now that I have the T/A, leaning towards installing it there. The car was originally an L69 (305 w/ Quadrajet Computer-Controlled Carb). When I purchased it last in late 2019, it came with a 350 (plain-jane as can be) with a Speed Demon Carb. I have a complete harness, ECU, fuel lines, etc. from my 88 parts car, waiting for installation.

Since it is a big project, I'm trying to break into smaller parts to minimize the time the car is off the road. Since the car is riding on factory springs, I have been planning to drop the rear end, clean and paint it, plus install new springs and struts. Figured this would be a great time to drop the gas tank and install the fuel pump. The L69 evidently came with an electric fuel pump as I have identified the wires leading to it and confirmed with the factory wiring diagram. The fuel pump relay at the front of the car is not active - the 350 has a manual fuel pump located at the front of the block providing fuel to the carb.

So, my question: Would there be any issue with me installing a new fuel pump in the tank, but leaving it unpowered until I complete the TPI conversion? That would leave the current manual pump drawing fuel through the non-powered new electric pump, but I think that is what is happening today... Hoping others might have direct experience with this, as I am only guessing right now that the original electric fuel pump might be still in the tank.

Hope that makes sense!

Also, what pump is recommended for a stock-type replacement? I could go with the Walbro 255, but seems overkill for my low-HP system.

Thanks guys!

(Some pics of the polished parts from back in 2018)

 

If the return line runs back to where the pump is inside the tank, then maybe use the return line as the supply line for the carb.