‘72 v8 gas tank and sending unit compatible with ‘69 i6

[Luke87gt]

Hi guys,

Local guy is selling a 1yr old gas tank and sending unit from his 1972 350 c10.

I’m considering picking it up to replace the 56yr old gas tank in my ‘69 i6 (truck has sat for many years).

Just want to make sure both the tank and sending unit are compatible, plug and play.

I seem to remember that the later trucks have a fuel system that doesn’t vent into the atmosphere, don’t recall if that matters.

I also seem to remember that some of the tanks had evaporative emissions control and some didn’t. Again, not sure that matters with the tank but I do see RockAuto has tanks with and without EEC

If anyone can help confirm, that would be helpful, thanks

[72c20customcamper]

I would take a look at it for venting concerns . The tank will physically fit the sending unit will not work . The I6 has 5/16 lines and the V8 will have 3/8 so you will either have to reuse your original or buy a new one .

[PbFut]

Venting may be an issue. Your original probably did not have vent or return lines. If the tank is out of a C10 it will have return and vent lines and the gas tank caps will be different. If the replacement tank is out of C20 or higher, then there will not be any vent lines but will have a return line and the cap will or at least should be vented.

[68 TT]

I don't remember what year it changed but the filler neck diameter is different at some point as well. The cab to filler neck grommet is cheap so no big deal. Just order the one for the 72 tank. The one from yours is probably hard as a rock and cracked from the years of sitting so it will probably fail when taking the old tank out.

[MikeB]

Should work just fine. Just use a 3/8 to 5/16 adapter. It's what I did with my 69 that's using a 71-72 sender. (My original 307 engine used 5/16 line.)

I assume the 72 setup will be vented, so you can either deal with that, or simply cap the vent line and use a vented filler cap.