My 86 IROC has the stock fuel pump on it and it has 2 lines running to it. What is the second line for? I think that it may be a vent, but I want to be sure that is what it is before I put my big fuel pump on it. I have a Holley high volume street pump for it and it only has 1 hole for the incoming fuel line, what should I do? By the way, one of the lines is bigger than the other, so which one is which?

 

I'm guessing its a mechanical pump. One line is fuel feed, and the other is the fuel return line. smaller is fuel return, bigger line is fuel feed.

 

so what should I do with my return line? Can I just leave it open?

 

I suppose so. Just be careful of flooding. I'm sure your using a fuel pressure regulator.

 

yes, it's the return line and no, you can't leave it open, 'causeI did that with mine and it got messy when I filled my tank up I just folded the rubber poriain over and zip tied it so the line was pinched, yeah I know real *******

 

So all I have to do is plug it up, (The return line I mean)? And no I am not running a fuel pressure regulator, should I, why would I want to? Sorry, but this is my first motor change, so I need all the help I can get.

 

you need a malory 3 port fuel pressure regulator...this has an outlet for your return line..

 

Man, those things are $80. Is there nothing else I can do? I know that isn't a lot, but when you start changing motors, everything is just $80-100. It doesn't take long before the bill is huge. What about a 1 way valve?

 

nickle and dime ya to death , I know. What was the fuel system before the swap..Carb, EFI? If it was efi the pressure from the pump will be too great. You only need 5-7 lbs of pressure. With the afpr the extra fuel is returned to the tank. There is also a vent line coming from the tank to your charcoal canister, Make sure this is clear. I wouldnt block or crimp any of these lines,IMO you would be asking for a fire.
I just read the above posts a little more,
Are you currently running a mechanical pump?
If you are running mechanical, you can use a cheaper regulator. the malory is good for 60lbs plus, good for regulating the fuel pressure when going from efi to carb. The stock electric pump pressure is around 40psi way too much for a carb. If you indeed are running mechanical you only need a regulator that handles 0-15lbs holley makes one for around 20.00.
hope this helps.

 

Hey thanks, yes it is a mechanical fuel pump, and I was running a carb system from the factory, you know the H engine code with a whomping 155hp. The $20 regulator is much better, that is what I will go with. Who distributes them, I looked through my Summit catalog, yes it is not the newist edition, but I couldn't find it. Do happen to have a pn or a resource. Again, thanks for your help

 

I know holley makes a 3 port that is adjustable to 12lbs I had it in my hand at the parts store but I cant find a part #. just call a parts store ..nappa carries them, ask for a three port for a carb setup.(low pressure)

 

Thanks, I will call as soon as I get home from Holland.