can i put a 1985 bronco 9''rearend in place of my stock 1966 f100 9'' rear?

 

U can swap 9" rears often, but I doubt that will work. Need to check out the spline count on the axels.. Your 66 will highly likely have a 28 and I tink de broco have a 31, at least in 85!!

Someone correct me if I am wrong.

 

Are you talking the whole axle assembly or just the carrier assy(pumpkin) or the axle shafts?
Carriers will swap as long as spline count is the same.
Complete axles will need modification to fit(length, spring perches, etc.).
Axle shafts will need shortened(I think) to fit the '66 and also spline count must match.

 

Short answer is no.

Long answer is yes you can swap the complete rear in with mods. Hangers will have to be moved, springs will have to be delt with. You will need the power disc brake upgrade, driveshaft connections may be different, etc.


John

 

The Bronco should have 31 spline axles and your truck should have 28 splines. The entire assembly will be considerably wider than your classic.