I'm switching a car from a 8 3/4 to 9 inch. Both have 1350 ujoints. Any guess on if the driveshaft will need to be lengthened or shortened? I do not have a motor or trans in the car yet.

On. Dragster 8 3/4 to 9 inch ford 1 inch longer 4 link car

Similar for me, hard tail Dragster, went from 8 3/4 to 9” and my coupler was about 1 inch too short.

quote:

Originally posted by NEMO963:
Similar for me, hard tail Dragster, went from 8 3/4 to 9” and my coupler was about 1 inch too short.

How did you account for the pinion location difference?

My guess they welded the plates on to line rear end up in right location on dragsters you work off the pinion

Yes sir. It was an Older N&P car with 8.75 mopar, rear was welded in. Had Holzman race cars cut the 8.75 out, welded plates in the rear and welded up a ford 9” and bolted it in. Only thing we found didn’t line up perfectly was the trans to rear coupler 1” too short. Bought a longer one from MW and was back in business. Broke a number of 8.75 before the switch and after ran the same 9” for many years.

Did you notice any significant difference as to reduced ground clearance with the pinion on the 9 inch being lower in relation to axle vs. the 8 3/4?

I didn’t, but since my old one was welded solid and this one was bolted in we set the ground clearance to be the same and not sure where that would has located it in comparison to the mopar.