i need to put a return line on my dart when i go to efi. my car has the ECS system as it's a california car.

would the vapor return line that currently vents the bowl on the carb be suitable as a return line?

as far as the pressure line, i was planning to use the existing supply line with the pump mounted near the tank. i may reroute the supply line up the firewall and over to connect to the rail at the rear of the engine.

zedpapa

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1970 dodge dart w/225 /6 bored .040" over, holley 390cfm w/vac. sec., compcams 252s, clifford shorty headers w/2.5" exhaust w/flowmaster, f-body 11" front discs, aluminum A-833OD, 8 1/4 w/3.21 SG
soon to have 5 gears!!!

The return line should be close to or the same size as the supply line.

You may be better off with another stock supply line used as return line.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Yes it is suitable - its a 5/16" line just like the supply line is

However you will run into some other issues - it goes up into that vapor separator, before it reaches the tank vents - that vapor separator will be the restriction. When I was initially installing my TBI setup (18psi max pump, 13psi regulated) the restriction was too high, it would be 18psi no matter what I did. Solution - I cut the return hardline close to the right wheel well, ran short section j30r9 rubber hose to fabbed steel hardline, then I welded a different nipple into the sender and rubber to that.

You can also weld a bung into the filler tube. Join the return hardline coming from the car to another piece of hardline, run it through the trunk floor, then make a loop up and point it down at the filler tube. Weld a bung at the filter tube and join to hardline with another short piece of rubber.

On your hardlines, do the first step of a double flare and use only EFI hose clamps. My return line had lots of rust/sediment in it - I took care of that by unhooking both ends, then blowing carb cleaner from end under the hood through it until it came out clear on other side. Took about half a can but it worked....

Be aware you will still need to vent the tank by some means - a strong enough efi pump can collapse a tank without a vent.

Err - addenum - I was thinking about the line that comes out from the crankcase breather, and goes to the separator in the trunk. I know that was 5/16". I'm not sure about the carb bowl vent. I didn't have a charcoal canister on mine. I think my original carb bowl was either vented to atmosphere or back into the air cleaner.

Hi my injection system been running fine for over 7 months now I used 5/16 line.There is some noise of fuel returning to the tank after the key is on and before it starts up.It clears the fuel rail of hot fuel/vapour lock.Use injection rated rubber tubing for your tank connections etc and you should not have any problems. Max.

At some point in this car's history I changed the tank to one with a vent and added a charcoal filter canister to cut down on the gasoline smell. When I went to EFI, I used the original supply line as the return, and added a new 3/8 line for the feed. I kept the vent line just as it was. I JB welded a 5/16" barb into the top front edge of the tank for the return line. It all seems to work OK. The filler and gasket are the originals, and I know the filler gasket at the tank is pretty old and crusty. . I suspect this would leak well before the tank collapsed. Not that this is a good thing. I also just capped off the original old vent that was int he filler tube.

I no longer had room for the charcoal canister, so I ran the vent line into the air filter. This seems to work OK. If I had room I would re-install the charcoal canister.

Sam

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On cars that came from the factory with efi the return goes all the way to the bottom of the tank with something seperating it from the pickup(to keep the pump from sucking vapor bubbles up). Doing this should affect the amount of vapor the tank gives off and might be something to consider.

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1970 Vitamin C Duster 225 2bbl 904 eventually turbo efi r154 5 speed

1969 B5 blue roadrunner 383/727 soon to be turbo slant (JK)

1972 Barracuda was green 318 who knows?