I have a 1998 f150 that came with the 8.8 drums

i got a 9.75 with disk brakes...

problems i ran into and yet to finsh..

the 9.75 is larger so your driveshaft might be to long...
Mine happens to be to long so im going to shorten or lift the truck..

another thing is brakes...
need a new mastercylinder... I think something with brake fluid being able to go back into the lines.... I got mine not to long ago so if that is a problem i can replace for free. Will find out once im finshed...

Um U-bolts and shocks all good..

the rearend is out of a 2001 3.55 limited slip..

One more thing the 9.75 is wider then the 8.8 and im told by 1" so i ordered
spacers for the front... And 97-98 studs are smaller then 99+ so you need
new lug nuts...

I dident see any post on this so i felt it was something that might help people

 

would I be able to put the studs from a 97-98 into the rear end (kinda like replacing the studs cuz they look the same size to me although I have not takin the time to measure them at work

 

I think it depends on what year 9.75 you have...

and its still 5x135mm just the studs are 2mm bigger in thickness i think
my rims still work but mine are aftermarkit i dont know if the stock rims
for a 97-98 will fit or not.

but if worse comes to worse just get new axles...
they are easy to take out and replace. But im saying in worse case....
I think you could change the studs but you need to talk to someone who deals with stuff like that..

 

I would be curious to find out if the base of the studs are the same. As for the 1 inch difference in width of the axles..... I swapped my 8.8 for a 9.75 and did not notice a difference. The track specs on all the 97+ axles is 65.4 inches. The 04+ axles are 66.9 inches. The front and rear track is the same for all the setups 4x4 and 4x2 so spacers are not required.

Regards

Jean Marc Chartier