Oldguard 7

I have noticed the 70 corvette's fuel pump only has one fuel return port on it and later vette fuel pumps have two ports on the bottom as well as being shaped different. It also appears the Holley equipped carbs used metal lines that run from carb to pump. I also do not see an in line feul filter. Can anyone explain the design?

ddawson

In order to pump it has to have an in and out. On most the outlet hardline will have a large fuel filter with two outlets. The little one goes back to the tank and the larger one to the carb.

Revi

In 1970, Corvettes with Quadrajets used two fuel lines to the fuel pump. A supply line and a return line. Holley equipped vehicles (LT-1) used a single line to the fuel pump.

A steel line went from the pump to the carb. The filter was inside the carb housing. There were no in line filter like you would see on a 69.

1970 L-46


1968/69

cardo0

U need to have a fuel tank that has a fuel return installed so the fuel enters the tank at the bottom and reduces vapor generated. I think all the Qjet cars with a fuel fuel return from the pump have this but not sure of the earlier cars without the return line.

If your modifying to pressurized return from carb inlet u need to run a vented gas cap otherwise with a full tank fuel can be forced out into the overflow and make its way into the charcoal canister - dont ask how i know this!

Dont know where the Holley carbs have their fuel filter but all the Qjets have in the carb inlet. I like the idea of the return line on the filter - makes it very easy to run a longer return line - but it really needs a restriction like 0.040" to reduce flow and vapor generated in the tank. BTW i modified my Qjet with a fitting on the inlet bowl for my restricted return all the way from the carb - very little chance of vapor lock with that. Also install a T there so i have an electric fuel press sender installed too - i can read fuel press at the carb inlet from the drivers seat (gauge is installed in the clock hole now).