swapping fuel tank help

[DESTRO]

My truck only has a passenger side tank. The drivers is long gone before I got the truck. It's also set up for dual tanks.
What I would like to do is swap the pass side over to the drivers side and eliminate the selector valve set-up.
Will I need to put a new sending unit or will the one for the passenger side work?? If I'm going to just have one tank, how many outlets do I need on the sending unit?? I see there is 1,2,3 set-ups out there. Also will my fuel gauge wire be affected once I remove the selector valve??

1977 chevy LB 350 carb

Hope someone can help me.
Thanks

[DESTRO]

can the sending unit from the passenger side be used on the drivers side??
Just want to make sure I have the parts before I do this.
Anyone??

Thanks

[ray_mcavoy]

Hi DESTRO,

The sending units are side specific, but with some longer rubber lines, you can probably make the pass side unit work on the driver side. Replacing it with a unit meant for the driver side would give you neater line routing and less chance of the lines getting pinched or chafing on the underside of the bed though.

The 1 vs. 2 vs. 3 line sending units are based on various engine options and emissions requirements. The 1-line units are obviously just a feed to the fuel pump. The 2-line units add a vent that is usually hooked up to a charcoal vapor recovery canister. And the 3-line units add a return line that's hooked to a special fuel pump (that has a return outlet). I think the return line setup was used primarily on vehicles with AC and/or larger engines to help prevent vapor lock.

The 1977 dual tank setup uses the dash switch to connect the appropriate sending unit wire to the gas gauge. So as long as all the dual tank wiring is still intact, removing just the selector valve and leaving the switch flipped to the driver side tank should allow your gas gauge to work normally. Or, if the wiring is messed up, you could just splice an extension onto the existing sending unit wire and re-route it over to the other side.

[DESTRO]

WOW,
Now that's an informative reply. Thanks alot
Well since I'm gonna have to buy a new sending unit, which one would you reccomend?? 1 or 2 outlet? I should probably replace my fuel pump, it's getting up there in age. So this would be a perfect time to upgrade the whole works to the best set-up. Which one would that be ya think?
I have no charcoal canister so should I use a vent one??[2]

Thanks for all the help so far.

[MTCK]

Just out of curiosity why do you want the tank on the drivers side? You can accomplish everything you want to do, IE eliminate the selector valve without moving the tank to the other side. The stock fuel lines already run down the inside passenger frame rail. That being said, you can look at your current setup and see if your selector valve is a 3 port or a 6 port unit. Then look and see if there is a return line from your current fuel pump. If everything is working fine I would just bypass the selector valve and leave the switch on the right tank position and be done with it. Good luck.

[DESTRO]

Originally Posted by MTCK

Just out of curiosity why do you want the tank on the drivers side? You can accomplish everything you want to do, IE eliminate the selector valve without moving the tank to the other side. The stock fuel lines already run down the inside passenger frame rail. That being said, you can look at your current setup and see if your selector valve is a 3 port or a 6 port unit. Then look and see if there is a return line from your current fuel pump. If everything is working fine I would just bypass the selector valve and leave the switch on the right tank position and be done with it. Good luck.

The reason for the move is that i'm going to take the frame all the way down and need to replace the tank brackets, So for just ease at the pump I want it on the drivers side. I'm going to be replacing all the lines and stuff anyway.
Might as well put it on the side I want.

[DESTRO]

For what I have gathered, I think I'm gonna use a 2 outlet sending unit.
Where and how exactly should I vent the vent since I have no charcoal canister??
Would a one outlet be best?? Are the 77 gas caps vented??

That should be the last info I should need . Thanks everyone for all the help so far.

[TheWhiteElephant]

Originally Posted by DESTRO

For what I have gathered, I think I'm gonna use a 2 outlet sending unit.
Where and how exactly should I vent the vent since I have no charcoal canister??
Would a one outlet be best?? Are the 77 gas caps vented??

That should be the last info I should need . Thanks everyone for all the help so far.

Did you find your answer yet? I am on the same boat. I'm thinking I can just use a breather/vent like a valve cover breather?