Replacing 78' gas tank with older model

[deacon]

I am replacing my at 16 years and rusted tank with a reconditioned one from an older model. The new tank has a new sending unit, etc as well. My question is that obviously the older tank does not have all of the evaporative lines that the oem did. The fuel supply and filler overflow are obvious. I was just planning on plugging the return line that came off the ADFA. Anyone have experience converting to an older model tank. I was told that it is done quite often. Of course all of the smog gear was long gone before I got the car from the original owner. Thanks.

[baltobernie]

I'm not sure why you want to plug the return fuel line. Webers allow only 3psi max; without a return line you are relying on the fuel pump not to exceed this.

All fuel tanks require venting, either to the outside air or via a one-way valve to allow air in to replace the fuel going out; otherwise the car won't run correctly and the tank or lines will be damaged. Some simply drill a tiny hole in the gas cap to vent the tank, but if your state has emissions, that won't do.

Evap emissions controls in old cars are a PITA, due the limited availability of OE components. Substitutions with currently-available items from other cars will work, but there doesn't seem to be a cross-reference anywhere. The evap stuff doesn't affect performance, lessens the gasoline stink in your garage, and makes your car saleable in states currently under emissions inspections. It is almost a certainty that all populous states will eventually has some sort of inspection.

[mikem48083]

I am replacing my original gas tank with a new tank I purchased from International Auto Parts #17057. The new tank does not have the (3) evap tubes. Did you ever figure out what to do with the open lines that were used with the old tank?
Thanks for any help you can provide on this...

[124JOE]

the three evap tubes go into one bigger one
is there a single vent on the new tank?

[mikem48083]

Thanks for the reply, I really appreciate it. Yes the new tank has one bigger one, but the old one did too. The old one actually has one by itself on the top side of the tank and three clustered next to each other also on the top side of the tank. The one by itself looks like it goes to the filler overflow. The three clustered next to each other have an adapter that leads into one hose. This is the hose in question and I'm not exactly sure where it goes at this point, but I think it's related to some sort of evaporation function.

[124JOE]

the three tubes are vents for each section
mabey the new tank has a internal vent system that eliminets them tubes

so theres no second vent

i hope someone on here knows

[mikem48083]

That makes sense. I'm just wondering if I need to do anything with the tubes that used to use this old vent system?