9 inch rearend swap

K

kendall

Senior Member
hello everyone,
9 inch rear end out of what??????..... would be a good bolt in for a F1? i am looking for a little better road speed with out rapping out my flathead. right now going down the highway at 40 mph the engine is running 2000 rpm. i am thinking a 9 inch with 3.50 gears. .......but what would be a good bolt up, i heard a 71 F100 is close. what do you think????

thank you.
 
I have used everything from a 55 Chevy rear with 3.8 gears to a 8.8 with 3.7. Nine inchers are becoming expensive, nice to know you have alternatives.
 
Any of the 57 to 80's?? F100/F150 rears will fit. So I am told, they are the same width and have the same bolt pattern (5 X 5 1/2). I also heard that the spring mounts are in the same place.

I think in the 80's sometime the rears became wider. I don't know what year this occured. Measure it if you find one.
 
I used a 9" out of a 1972 two wheel drive ford pickup. Width is perfect for a F1. Do a search on Ford 9" you will get all the specs you need to start your search. I have mine behind a T-5 and love how my flatty runs at freeway speeds.
 
An early bronco rear is too narrow and 72 and newer will be too wide. I prefer 58-early 72 rears from a half ton truck. The housing looks different on a 57 but will work. The spring perches will be in the same spot. Early 60s the shock mount moved from the spring perch area to brackets welded onto the housing. The 57-60 housing has a smooth back on the pumpkin and is centered from the rear which may be of interest if you can see it from behind. I have 59-60 rears in all three of my F1s.
 
I have a 9" with a 3.25 ratio in my 53 F-100. Mild flatty, and stock ******. Cruises @ 60 just a lil over 2000 rpm's. Best bolt on I ever did. The axle came from a 71 F-100.
 
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