Crafty12

I have a 71 that was originally equipped with a Rochester carb. That carb is now gone and replaced with a Holley. That leaves me now with an unused return line. I just replaced the gas tank and bought the one with the nipple for the return line. What is the best solution to deal with unused line and port?

The PO blocked off the return line with a bolt back up near the fuel pump. Should I cap it off at the tank, or hook it back up and continue to use the plug at the front end?

Also on the subject what should I do with the vapor return line? I swapped the separator valve onto my new tank and have that hooked up. Should I hook that line back up or plug it back at the tank. Currently its hooked up to the canister, but the PCV line and signal line aren't hooked up. I don't have a vacuum port on my carb, and would kind of like to just do away with the vapor system all together. I have a sealed gas cap currently.

Any help would be appreciated.
Thanks!

TimAT

Cap both ends of the unused lines. Save them for later. My 69 does not have a return line. I sort of wish it did. Make installing an electric fuel pump and regulator much easier.

Alan 71

Hi C,
In 71 didn't the return line run from the fuel pump back to the tank?
Have you changed the fuel pump too along with the carb?
If you don't use the vapor control system you'll need to change to a vented cap. This sometimes leads to a gas smell if the car is parked in a garage.
Regards,
Alan

69Vett

Brand of carburetor makes no difference concerning return fuel line, you original setup supplied a return line from the fuel pump back to the tank. I would suggest connecting things up as original to avoid things like vapor lock from your fuel boiling, because of no return line.

Iceaxe

If you unplug the vapor line at the seperator valve and throw everything else in the garbage you will have the exact same vapor recovery system that came standard on the 1970 49 state Corvette. Only CA Corvettes got the vapor canister and recovery system in 1970. Keep your non-vented gas cap.

I've not using my fuel return line as I switched to an electric fuel pump. The return line is currently capped in the engine bay in case I ever decide to use it. Not sure if that's the best solution, but it works for me.

SH-60B

Cap off the unused lines, use a vented cap. I "vented" the existing cap. Been that way for 17 years, never had a vapor lock problem.

Iceaxe

He installed the seperator valve on his new fuel tank which vents the tank, so installing a vented fuel cap would just be redundancy. It wouldn't hurt anything, but it's not needed. This is how the 1970 49 state cars came from St. Louis.

ddawson

I hooked my return back up with my Holley Clone.

With today's fuel I wanted all the help I can get on hot starts.

SH-60B

OK, do whatever floats your boat . Why respond to me though?

D_Williams

If you do block off the vapor system, you will need to use a vented gas cap. Currently, with the canister disconnected from the PCV line, the vapor system is acting like a vented cap (because the engine can't draw the stored gas vapors to burn).

I'm pretty sure that all 70's came with sealed gas caps. The Cali cars had the vapor system while the other 49 states came with vented gas tanks (the tanks have a built in vent).

Crafty12

Who am I to argue with Alan when it comes to a 71 I checked though and my fuel pump only has two ports. A hose port for the input and a threaded port for the output. Maybe a previous owner changed out the fuel pump?

As for the setup. I think I will re-attach the return line to the tank and just leave it plugged in the engine compartment. On the other side I will hook up the separator valve to the line, and cap that line in the engine bay as well. I'll put the canister in a box and put it away.

With both of those lines blocked will I need to run a vented cap? The tank itself is vented already, so I don't think it matters which cap I use. I currently have a sealed cap.

D_Williams

Yes, you will need to use a vented cap. Your tank is vented through the vapor system, so blocking that will seal your gas tank.