Guys.
Warning. The Mustang tank article here in FTE does not work with the '65-66 trucks as it is written.
Today I helped a buddy try to mount the Mustang tank referenced in the tech article here at FTE in his '65 F-100.
The frame is about 2 inches to narrow for it to fit inside the frame the way it does in the article.
What we are going to do is drop the tank mounting flange 1" below the bottom of the frame and notch the that part of the frame so the top of the the tank will fit inside the rails. You guys with the later model trucks will know what I'm talking about.
Doing this makes the bottom of the tank lower than it should be but for his particular application it will be o.k. The measurement from the flange to the bottom of the tank is 7" so be careful if you decide to do this for ground clearance. With the way we are going to do this, this makes the bottom of the tank 8" below the bottom of the frame.
Unless you want to trim the bottom of the frame like we are going to do to make the tank fit up inside the frame the way it does in the article, you need to look for something else to go in your truck. My opinion, for what it is worth, is that since this is involves the very back of the frame, I don't think it will weaken the frame in any critical way.
I will try to take photos and keep a journal as to how this experiment goes and post them when we get the job done.
FYI>>> The Mustang tanks go in the 61-64 trucks o.k. because the frame is wider in the rear just like the article says.
Skip4274
4everFord

 

Skip was this a 2 or 4wd truck?


John
jowilker
Club FTE since 01 01


66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.

 

John. It's a standard SWB 2 wheel drive. I guess the frames on the later models are narrower than on the older trucks. I am going to measure the frame opening at the rear on my own 63 and then on Jacks 65 so I can post some numbers. We physically couldn't get the top of the tank between the rails on his truck, but it went right in on mine.
I don't know about the 4wd. There aren't many down here. We don't have a lot of use for 4 wheel drive cause it don't snow around Houston like it does in Illinois or Michigan
Skip

 

I hear you Mr. No Snow Guy, I never had a use for one either. I understand that the frames are narrower on the 4X4 so this why I posted the question. It does seem strange that Ford would narrow the frames on the 65-66. Would you measure the tanks as well to see if there is a difference there?




John
jowilker
Club FTE since 01 01


66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.

 

John. The inside of my frame measures 29 3/4" from inside edge to inside edge. I haven't measured the distance on the later models, but they are considerably more narrow than this.
As with anything else, it can be made to work, but I just wanted to give everyone a heads up. From the photos in the tech article here, it just looked like a drop in. Nothing, I mean nothing, is ever as easy as it seems
Skip

 

Skip, I will go out tomorrow and slid under the ol red truck and whip the ol tape measure on his butt end and give you a professional measurement.


John
jowilker
Club FTE since 01 01

NC Chapter


66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.

 

Hey guys there were different size fuel tanks in the mustangs too
John

 

Fatforty.
Mustangs had 16 gal. tanks up through 1970 and they are physically all the same. In 1969 Mustang offered a 20 gal. unit as an option and in 1970 they offered a 22 gal. tank option. Probably to accomidate the big block Cobra Jets and the like.
The lengths and widths on the tank, the mounting flange and the depth of the tank measured from the flange down are the same on all the tanks. The only difference in the tanks is the height of the tank measured from the flange UP.
The problem is that the top of the tank (the same as the bottom) is 28 3/4 inches wide. This means you have to have at least 29 inches clearance between the inside lip of the frame rails for the tank to mount properly. The 65-66 trucks don't have that clearance.
Skip4274
4everFord