I have a 51 f1 and am trying to find out what rearend will fit this truck. I'm after a 9" and was told a 68-72 f100 rear would fit. THe junkyard said he had 1 but his measurments dont seem to work. He said he had 54" from backing plate to backingplate and 7" fromn backing plate to center of spring perch. The rear under the truck now measures 57" and 9" resectfully. The rear he has wont work' am i right or wrong? What is supposed to fit? I"m also trying to figur what radiator will fit with ease and what seats will fit easilly/ thanks

 

You're right - looks like the one he has is from a late 60's/early 70's Mustang/Comet/Fairlane family. Check out this link...

[http://hiqties.hypermart.net/9inch.html]

 

he might but its still in the truck so maybe someone added it on, I dont know what it is i never saw it myself. do you know what fits though?

 

There have been several threads on here about the 9" swap with our trucks. You might want to try the search. Basically '69-'72 F-100's and you move the mounts.
I run a Dodge full-size van radiator, dropped right in. You didn't say what motor you're runing, but with my 302 w/passenger side water pump, the Dodge worked great.
Seats....well, that's a whole different story. Buckets? Bench? I'm putting in buckets from a '88 Cougar.
Good luck and have fun!!

 

that's why I always measure rearends to the outside. I guarantee that the newer trucks had wider brake shoes and drums and would therefore have a different offset. Measure the outside, hub to hub, and you will get about 61" on the 57-72 truck.

 

[updated:LAST EDITED ON 03-Aug-02 AT 09:00 AM (EST)]what do you mean outside to outside? with the drums on or off? how do you get an accurate measurment with it still on the truck?
what is the width of these rears?



thanks!!
gwilkrrs
51 f1

 

[updated:LAST EDITED ON 03-Aug-02 AT 08:58 AM (EST)]what year dodge van radiator did you use? how much work were the seats to get in. i have buckets on a wood box but would like to get new seats without the wood box underneath

 

[updated:LAST EDITED ON 03-Aug-02 AT 09:03 AM (EST)]I couldn't tell you the year of the readiator. I picked it up for $70 from the guy who built my heater core. I fabricated risers out of 4.5" channel for my buckets.
And truckfarmer's right, my mistake. '57-'72 rears.

 

[updated:LAST EDITED ON 03-Aug-02 AT 09:15 AM (EST)]but how do you measure the rear acurately while on the truck? take the wheels, drums off and measure from the axle flange to flange?
did the rad just bolt in? how do you do the search to check all postings on subject? and is 61" the right width for a 51?

 

you will probably need help. Leave the drums on, measure from where the wheels would mount. There is less guessing if you use a straightedge to measure side to side.

 

and 61" is the right number for a 51?

 

Yup, the radiator dropped right in.....I had to modify the mounting fins a bit though. But just used tin snips.

 

so if i understand, the 57-72 f100 raer will work but i'll have too move the spring perches. is the 5 lug pattern on this rear the same 5 lug as on the mII front end? some say no but i'm trying to verify this info. i'll have to look into my rad because my waterneck is on the driverside

 

Those rears (9" from 57 to 72) will work without moving the spring perches. You may need to add caster wedges to adjust the pinion angle, but you can purchase them from places like NAPA. Some shock mounts may need to be moved, but that's easy to see and change.

I'm not sure about the MII bolt pattern but the truck pattern for half-tons is 5 on 5 1/2" (5 bolts and the diameter of the pattern is 5 1/2 " center to center) You'll just have to get out a tape measure and compare the one you have on the 51 to the MII pattern.

All 1/2 ton Ford truck rear axles, at least '48 thru '72, measure 61 1/4" drum to drum.

 

thank you!!! I'm going this weekend or monday to get the rear so i'llsee about the shock mounts and I'm thinking i"ll have driveshaft lenght problems too. '''ill keep all informed od progress