ok im a little confused, i put a new Holley fuel pump (110gph) and noticed that it has two connections which im sure is the fuel input and output but as for the stock fuel pump there are THREE not two connections. What exactly does the other one do? Im trying to figure it out. I looked in my manual but dont see anything on it. Do you guys know where it goes?

 

The 3rd one is a return line back to the tank.

It's a very good idea to keep it. Instead of dead-heading the fuel when pressure is high enough, it returns the excess back to the tank. This has the effect of keeping cooler fuel going to the carb.

Unless you have a mongo engine, a stock replacement fuel pump will keep up with the demand. My original pump (at least the one that was on the engine when I got the donor car) was shot, but the AC replacement I got from Checker (Kragen in your neck of the woods) has performed just fine for 5 years.

 

well the engine going in is kinda big and i know its going to be thirsty for fuel. I would like to keep it if it has the effect of keeping cooler fuel going to the carb, but since my holley FP doesnt have that extra 3rd connection, would it be ok to not have it? In other words block it off some how.

 

Okay, I'm supporting about 325 gross horse. That'll probably increase by about 50 in the near future, and I've got no qualms about keeping the stock-type pump. RB tells of supporting a nice-running 400 with a stock type pump. If you listen long enough, he'll even tell you that a light-weight pushrod will help more than a "bigger" fuel pump like a Holley.

The benefits you'd be sacrificing will most likely outweigh the benefits you'd gain with the non-return Holley. I'd return it.

But, if you really want to keep the Holley, block off the un-used return line.

Or, get a return-type regulator and connect the return line to it.