I am going to have to pull the gas tank in a 86 6 cyl I just bought to change the fuel pump.Is it hidden behind the inner fender ? Is this a "straight forward job"? I see the filler, but not the tank it self. Thanks

The fuel tank is in the center of the car. It is long and narrow. There are a couple of straps holding it up. Not that bad of a job, just be sure to disconnect all the lines before trying to drop the tank down. You can bust where the lines go into the tank. There only brazed in or something, and then you'll have a leak.

Try this.

http://fierodomain.com/content/view/111/100/

After jacking AND placing the stands in place (be safe) remove the center wide strap that you see located half way down the tank in this picture. Use your jack with a flat plate or a piece of wood to support the tank, than remove the forward and aft straps using a 13MM deep socket. Slowly lower the tank enough to gain access to the connections and fill tube. Continue to lower the tank all the way to remove the pump.
Of course remove as much fuel as possible to help in removal.

Remember to BE SAFE as the tank will be heavy unless most or all of the fuel is drained.
Also replace the "O" ring that will be under the lock ring.

SO THE GAS TANK IS LOCATED WHERE THE DRIVESHAFT WOULD ORDINARILY BE ?

Yes, the link sjmaye posted covers it pretty much step by step.