8-1/4 to 8-3/4

BBLM23 said
Yes, you need a different (shorter?) driveshaft.

I was just looking at the driveshaft page on Mancini's web site:

http://store.yahoo.com/chucker54/driveshaftkits.html

They've got cut-to-fit 7260, 7290 kits. Bolt-in 7260, 7290, 1350 kits. And lightweight kits.

What's the difference with the 7260, 7290 & 1350 kits? What's this "slip yoke" thing all about?