I need more gas!!! I am building my Comet GT to be a highway cruiser. With 3.00 gears, a 5 speed, and a very mild engine, it should get decent mileage. Now I need to extend the in between fill up times. Looking though the Mustang catalogs, I see the 70 has a 22 gal tank. Bingo. A bunch of dollars and days later, it was delivered today around noon. Initial measurements found outer flange to flange is 32 3/4" wide, and 25 5/8" deep. The top of the tank is 2 3/8" above the flange. I initially cut a hole 32 7/8" wide (centered) and starting 4" from the tail light panel, 25" deep. I knew I wanted to completely remove the horse shoe shaped depression in the trunk floor so depth was not an issue right now. I wanted to drop it down so it doesn't protrude into the trunk any more than I have to. I found after bolting a valance on, I can move it all the way back to the front of the rear frame rail. It clears the valance with no problem. I can make the rear drop mount 2" down and it should fit in there nicely.
You can see it dont sit any lower than the 65 Mustang tanks that I use. I had already converted this over to a 15 gal Mustang tank. Oh well.
I cut the rest of the trunk floor out, using the existing drop for the front cut. Then I just squared them up.
Something to consider if you plan on doing this. For some reason the tank filler is offset towards the right side by 7/8". Not sure why but keep it in mind to keep the filler centered on your tail light panel filler tube. I smoothed out my filler so I kept the tank centered.
As im sure you noticed the added capacity of the 20 and 22 gallon mustang tanks are above the flange if you keep this flange even with the rear ofhe trunk floor you cannot see the tank from the outside of the car
I know I could have raised the tank but my goal is to make the trunk space more usable. Standing, you wont see the tank any more than a normal car. Next step was to mount the tank to the rear drop and level it so I can make the front drop.
Great job on adapting the Mustang Tank. This is something I may consider when I get a chance to build a Maverick for myself.