14b vs D70HD Driveshaft lengths

I lowered my 1989 r3500 that came with a 14b in it. I swapped to a full width D70HD rear into the truck to gain the width. After months of working on the truck rebuilding everything. I went to install my two piece driveshaft. Low a behold it was too long. Pressed on the grease zurk and compressed the rear half onto the front half splines completely and it was still and inch to an inch and a half too long. My question is. Is my problem with the the swapped rear or lowering the truck or a little of both? Does anyone have a rear part of a drive shaft from a D70HD truck that they can measure from center of u joint to center of u joint for me?

Both.

Lowering the truck will decrease the necessary length of the driveshaft.

The pinion on the D70HD is longer than that of a 14 bolt (making the yoke is closer to the transmission).

If you need a shorter shaft, drive past a fitness center.
If you need a longer shaft, drive past the playboy mansion.

Edelbrock said:

If you need a shorter shaft, drive past a fitness center.
If you need a longer shaft, drive past the playboy mansion.

Click to expand...

What if I just need rest?