56 f-100 rear gas tank question

I want to place the gas tank in the back of the frame.I've read on here that late 60's mustang tanks work.Tried search function with no luck.Which tank to use and what has to be modified for it to fit.I'm sure the spare tire support will have to be removed.How about the crossmember which supports the shocks.Thanks for the help.

 

'65 to '68 work well. The filler is in the middle and will end up poking through the bed.
The spare ends up in the bed.

 

Will the mounting flanges sit on top of the frame.I have a 2 x 4 inch crossmember welded across the back of the frame so no problem removing the spare tire mount.Thanks for the input.

 

Go to ford truck enthuasist. There is a whole write up on how to do this. The mustang and cougar tanks will fit. The sending unit for these tanks will work with your orginal gauges also. I bought my tank from the rcommended site there also. about 220. with sending unit and shipping. Hope this helps.

 

http://www.ford-trucks.com/article/...ing_a_Mid60s_Mustang_Tank_In_A_1953_F100.html

http://www.ford-trucks.com/forums/665383-gas-tanks.html

Hope this helps

 

Thanks for all the info guys.

 

I used a 21 gallon chevy van gas tank (1978-1983) and straps, moved the rear crossmember back about 4 inches (to the back side of the spring perch), cut a hole in the frame, welded in some tubing to run the filler neck through (the gas filler is now on the driver's rear fender)

 

I've always been the Odd Duck and this might prove it beyond doubt. I have also never understood why anyone would want a Gas Tank behind the rear axle or why you would want a Gas Cap in the floor of any Truck Bed. I also own and am building another 53 F-100. I wanted more fuel than a stock tank held so This is what I came up with. Actually this is an improved version of one I did back about 1965. They are stock 53-55 F-100 tanks and mount right up, fuel is low and won't make the tail wag the Dog around corners (I live up in the Mountains). I also pull from both tanks at the same time so only need 1 sending unit and no tank switch. I could have used the stock filler for both but don't like the Donkey **** sticking out the corner of the Cab, however they do both fill from the same place at the same time. You can mount 53-55 tanks on a 56 simply by changing the 56 running board mounts to 3-5 style.
The Wizzard

 

Also the Chevy s-10 (i know i know) tank from a 4 wheel drive will work behind the axle. I'm considering it, but also would rather it not be behind the axle. Might just leave it behind the seat.

 

65 Mustang tank between the frame rails, I did just about the same as in this article.
http://www.ford-trucks.com/article/...ing_a_Mid60s_Mustang_Tank_In_A_1953_F100.html