Do I need a different driveshaft?
 

I have an '86 Mustang that had a V6 in it, I pulled the V6 engine and trans out and put in a HO engine and trans from an '86 Mark VII in it.

I went to hook the driveshaft up a few minutes ago, but its about an inch or so too long. Ive read that driveshafts are the same for c4, c5, and AOD's though.



Is there anything I could be doing wrong?

I was shoving the driveshaft into the trans pretty hard to try to make sure it was in all the way. I even took it out, twisted the shaft, and put it in again and acheived the same results.

Which drive shaft are you tring to use? The v6 or the one from mark 7. The mark 7 is a longer car,the shart will be longer a 6 cyl shaft I don't know for sure but seems to me it would be longer also to make up the difference between the length of the v6 and v8. Don't force the shaft,you should be able to go in an extra 3/4 to 1 inch then pull back and hook up to pinion, with out this clearence your drive shaft will bind your drive train and cause you some problems. I would get a drive shaft out of a v8 mustang or have yours cut to proper length.

im using the V6 one.

I dont have the one fomr the mark VII

Measure from the rear seal on the tail shaft to the pinion on the rear end, then measure the drive shaft from the yoke that bolts to the rear end and put a mark using your first measurement,it should be 3/4 to 1 inch past the tapered part of the input shaft on the front of the drive shaft.