pik

Looking for advice! I am replacing my camshaft, 2 worn lobes on the old one. I noticed that Bubba has replaced the fuel pump with a Big Block (I think) fuel pump. ie it does not have a return line fitting. My return line is blocked off with a bolt. My problem is that if I put the fuel pump back to original plumbing what affect will this have on the carb.? It is a Rochester Q jet. My priority is starting the engine quickly and break in the new cam. What would be the affect of less fuel pressure to the carb (if the return line was hooked up)? Should I put Bubbas system back to use thru break in of the new cam??
Thanks in advance for any suggestions.
Andy

Stewart's74

I dont think it matters. Most aftermarket fuel pumps do not have a return line. If you get a stock fuel pump with a return fitting, make sure bubba still has the line attached at the tank. Dont want fuel all over the place.
I'd make sure the return line is blown out before re-using it. My guess is that is has junk in the line. You dont want that to get in your fuel.

Cookwithvette

In a mechanical fuel pump, pressure is provided by a spring pushing a plunger, the pushrod hits a lever that resets this plunger. This way the pressure cannot go above what the spring can push. If the needle is closed at the carb then the plunger just stays down. With a return line the plunger will cycle every time. If the needle at the carb is closed (and pressure in that line is normal) then the excess fuel is pumped back to the tank. When the needle opens and pressure drops in that line no or relatively little fuel is pumped back to the tank. Your pressure should be the same with either pump.

BSeery

I have an aftermarket (Holley Street) pump on my engine. I have had the return line blocked for 2 years now with zero problems.