Help ! I've been stockpiling parts for my rebuild. (80 F-250 4x4 ext cab with 351m).got u-joints from local chain parts store. They told me all were the same. They lied!!! After 3 plus hours of fighting to get 35 year old parts out, went to install all three driveshafts and found out there was a difference in some. My question is does anybody know part numbers for all five u-joints. Two on the front d/s,and three on the rear d/s.

 

When I changed my U joints my front and rear joints where actually different and if i remember correctly the back one where it connectes to the yoke have a slightly larger pair that fit in. but thats beside the point

take your old ones up to the chain store of you choice ( I prefer Orilieys ) and set the new ones next to your old ones so you know what to get, the way they set their system up is just retarded so you have to be smarter than it to get it to pull up what you are looking for

these chain stores just have one kind of u-joint in the system for my f100 so we had to do some digging at the store on there computer. at one point I had about 5 or 6 different ones on the counter.

 

Thanks for the advice. I ended up doing just that,but at another location. The store I usually go to was pretty good,but now they're dumber than rocks(sorry rocks)! It appeared that the joints at the transfer case are smaller(1.062 ,1.125)

 

Also, it isn't likely you have a 351M. The F250's had 400's while the F150's had the M. However, the differences cannot be determined without measuring the stroke, as only the crank and pistons are different.

 

Definitely have a 351m. Just had a new one built. And all the markings and vin numbers identfy it as so. I have a very early run number (00134). It sometimes drives me batty because I sometimes have to identify as a 79!

 

Pretty! Ok, you would know. What pistons did you use?

 

Whatever ones the builder put in!!!! Had the break in already, and it sounded GREAT with open headers!!!! My truck is a camper special, but it is the under 3800lb rating??? didn't understand the reasoning there. I'm the second owner,and have made some changes to the grandpa truck I bought. Pretty much have it all back together except for exhaust. Going with thrush turbo ,because they were free and 2 1/4 " pipes exiting in front of rear wheels. Chomping at the bit to drive it again !!!!

 

I'm sure you are chomping at the bit! Let us know how it goes.