3550's were put in some of the 94/95 Saleen 351's for sure. N/A 351 cars got them, I think all the supercharged 351's got the 6 speeds.

Anyway. If I remember right there are two ways to do this.

1. I used to see a billet almn spacer for the rear of the driveshaft that goes between it and the yoke in the rearend. I think is like 3/4 " or somehting. (if I can find a source and part number I will PM it to you.)

2. You get a custom length driveshaft.

It can be done.