[mosesburb]

Ok, now that you guys have speculated about GM fuel tanks, allow me to present some facts. The engine supply pipe on V8 GM sending units in this vintage is 3/8. The ohm range is 0-90 on both the '72 and (in this case) up to '91. The 0-95 or 0-100 ohm aftermarket sending units are crap in my opinion. They are inexpensive, but unless you enjoy dropping your fuel tank to change them, I highly don't recommend them. I needed a third one in my Suburban and said screw it and bought the high-dollar GM replacement and my gauge is dead-on now. It wasn't before?? No, it wasn't. The gauge is looking for 90 ohms when full and the sending unit puts out 95 or 100 (depending on whose literature you read--I've seen different numbers from the same company on the same unit (they measured 100 in my testing lab)). The problem with this is, being the gauge is looking for 90 ohms when full and it is seeing 100 ohms, the needle is going to spin way past full and stay there a long time until the fuel level drops to 90 ohm, where it is still going to read full, but you have already used 10% of the fuel in the tank. Is it a problem?? To me, it is. Where I go, I NEED to know how much fuel is in my tank. Not an approximation that is off by 10%. Now, the problems are not just accuracy. One failed when the seal that is supposed to seal the electrical terminal through the top of the sending unit failed because they used Chinese rubber. That created a nice fuel leak. Fuel out, dirt in. Not good. The second one had an electrical failure. Now the third one that I got to replace the second one was bad right out of the box. I hooked my Fluke meter to it before I installed it and it was nowhere near any range that GM ever used. That was it. I ponied up for the GM (gasoline) unit and it is probably the most accurate fuel gauge in my fleet now.

Now, on to the tank. I can somewhat understand the desire to put a new tank in it, but why not get one from a wrecking yard?? We are not in Iowa, and so long as the donor didn't come from somewhere other than here, the worst you would have to do is take it to a radiator shop and have it cleaned. If it comes back ugly, shoot it with a coat of Krylon 1403 Dull Aluminum and it will look brand new. The nice part of doing this is the GM sending unit in it might still work (take an ohm meter with you to check it). Double score for waaaaaaaaaay less than $200 bones for just a tank (I have the GM/Delco part number for the replacement fuel sock on the sending unit if it needs to be replaced). Hell, if nothing else, get the wrecking yard tank and spend the $200 on a GM sending unit. I think that would be more win than a $200 tank and a Chinese sending unit. Also, if you have to (or want to) relocate the fill neck, the radiator shop can do that after they clean it. You can also grab the straps from the donor rig too. These have gone up dramatically in price lately from the dealer.

What tank to use?? I recommend a '73-'86 tank because they were carbureted. The tanks from the '87-'91 trucks have baffles in them that you don't need or want. There is also a difference in fuel fill pipe diameters. I forget exactly when they changed, but this may be a moot point if you are building your own fill pipe setup. Also, another FYI, the sending unit for a 31 gal tank is the same for a 40 gal. So if you find a nice 40 gal tank with a junk sender, but find a good 31 with a good sender swap them out and increase your win for the day.

Just some food for thought.