66 fuel tank in a 65

I pulled out the fuel tank out of a parts car 65 Gal I have and it turned out to be a 66. The tank doesnt leak and the fuel sending unit still works, and makes my gas gauge perk right up! To use the tank off a 66 in a 65, I will have to compensate for the shorter tank straps by using longer mounting bolts. I guess this will work. My question is will the fuel gauge in my 65 (20 gallon) be at all acurate using a tank and sender from a 66 (25 gallon)? I think it should be fine, but I want to know what you all think, or if you have done anything similar and how it went.

Ok, I think I can actually answer my own question. The guage is merely a translation of what the sending unit is doing. If it goes to half point on the sender's rheostat then the guage will say half, no matter what tank/sender you put in. The senders for the 65 and 66 are the same in makeup anyway, with the exception of the 66 sender being longer to compensate for the larger quantity. The rheostats are actually the same size, with the same amount of travel empty to full. It would be up to the driver to do the adjustments in his head as to how many gallons he has though going from 20 gallons to 25. So, the guage will be accurate according to what the sender says is in the tank if all is well.

Originally Posted by v8shadow

Ok, I think I can actually answer my own question. The guage is merely a translation of what the sending unit is doing. If it goes to half point on the sender's rheostat then the guage will say half, no matter what tank/sender you put in. The senders for the 65 and 66 are the same in makeup anyway, with the exception of the 66 sender being longer to compensate for the larger quantity. The rheostats are actually the same size, with the same amount of travel empty to full. It would be up to the driver to do the adjustments in his head as to how many gallons he has though going from 20 gallons to 25. So, the guage will be accurate according to what the sender says is in the tank if all is well.

...I knew you would get it if you just thought it through. As long as you keep the same tank with the same pick, there will be no change. If you mix 'n match - let's say putting the 25gal ('66) tank with the 65 pickup - there will always be about 5 extra gallons in the tank when the guage 1st says it empty. The '66 tank is deeper than the '65.

If I'm getting this right and you install the shorter tank sender in the taller tank you will also have a shorter pickup tube and not be able to get all of the fuel out of the tank.

Yep, you got it!