Thats how i had mine set up in the first place....but thats dangerous thats why im hooking the vent back up properly...and adding another port for fuel return
It is easier to solder a tube into the tank than it is to weld one in. Any radiator shop could do it with an electric soldering iron (like the one I have). Soldering guns don't hold enough heat. If you have had gas in the tank you will want to be careful to fill it with inert gas (if soldering with a flame) or water (if welding with a wire feed or arc welder). That way you won't blow the tank up from the fumes igniting.
I did this as well. Yes, I have to run a vented cap now. You have to be careful with the the vent line, as I found out. The vent at the top of the tank is actually a reeeeely tiny hole. When I put my car together I tested the fuel pressure and it was around 40 psi, right where it was supposed to be, so I figured the vent line was okay. A couple months later I started rupturing the rubber fuel lines...and then the car one day started running terribly, blowing clouds of black smoke. I burned up like a quarter tank of gas in less than 15 miles. Once I started troubleshooting, I discovered that fuel pressure was well over 100 psi! Not good!. Something must have clogged that tiny hole. I dropped the tank and removed the vent from the top and was able to drill out that tiny hole and now all is well... I think the main reason it is not recommended is because the vent line tends to be smaller diameter tubing and can cause the fuel pressure to be too high...but it is just fine on my car, once I removed the restriction. I guess the other reason is that when you do that you have now technically disabled an emissions device...the charcoal canister and all that is why they got rid of vented gas caps in the first place.
On my old '77 Maverick, when I was running EFI, the vent line was so rusted out that I couldn't use it. At that time I added a return port to the fuel sending unit, rather than weld/solder to the tank itself, and that worked well...
i forgot to tell about that part................mine run like $hit at first because of the same thing (the little hole) so i drilled it out with a 3/16 drill and then it ran great.
ive done severaly fuel injection conversions to carbed cars before, but never a maverick. i usually drill the smallest hole i can where i want the return to go into the tank at then take a center punch and hamer it into the hole make it biger and flareing the the metal inward. then i take a pipe thread tap 1/8 inch i belive and tap the hole. then i just thread in the fitting for the fuel line useing pipe thread sealant on the threads. never had any of them leak. ive done this to the pick up / level sending unit flanges and the tank walls with no problems.
well on mine i also drilled a bigger hole on top of the vent thing put a 90 degree copper elbow and than ran a new steel line all the way to the engine. i believe it was a 3/8 line.
Welding gas tanks should be left to the experts. that said i have done this b4 by taking a exhaust hose and running it to the tank and have a car on 1 end idling and the hose jambed in the tank.then wait about 5 min for the exhaust to push out most fumes and now you can solder or weld but solder is better as the tanks are thin metal
I added that particular return line about 25 years ago, so I gotta think about it. As I recall, I drilled a hole somewhere next to to where the feed line connected and then I found a piece of metal tube that fit snugly through the hole and used solder to seal the new tube in place. I believe it was NOT solder that is used for electronics. I think my dad called it "silver solder" at the time. Another idea I've seen is to drill a hole in the filler tube and tap so you can thread on a barbed fitting so you can run the return line there. This would mean you'd have to run the return line up into the trunk. The return line is relatively low pressure, but I'm sure not everyone would be comfortable with that. I still run EFI today. For a long time I was simply using the vent line (my current '72 Maverick has a very nice return line that is not rusted out), and I drilled out the vent port on the top of the tank so I could connect there. I have since read that this is not the best idea because as the tank starts to empty, the fuel coming in from the top of the tank tends to aerate, and you can end up with drivability issues if the air starts getting in the fuel line. Also, you then have to vent the tank some other way, like with a vented cap. Recently I have been doing some upgrades and have replaced my external pump with an aftermarket one that mounts inside the tank, and it came with a port on it intended for a return line. I had to cut a hole in the top of the tank for this, but I used a new '73 Mustang tank for this purpose (I wanted a larger tank as well), so I didn't have to worry about fumes. Anyway, you didn't ask for all that, but coincidentally I've had fuel return line stuff on my mind lately.
There is now an EFI compatible fuel sending unit that has the extra return port welded in beside the pickup tube. Great option I saw just after I converted the vapor line on mine to the return. If I had to do it again I would buy one of these and route a new line to that port. https://www.partsgeek.com/gbproduct...MI8-bz66S06QIVEUWGCh2s1gI6EAQYASABEgL7ffD_BwE
Its been a while since I looked at this but I think I needed to bend the pickup tube to match the Maverick one. Didn't actually get it so not positive on the fitment.
with my Pro Flow 4 multiport injection I'm running the new...Holley 12-305... setup I have now is...returnless...67 HPH @ 58 PSI. the return line I had before was another stock 3/8" fuel line I ran along side of the 3/8" feed line.
