Check the U-joint types at the rear axle and transmission...typical ones include the 1310, 1330 and 1350. I'm guessing you have a 1310 at the trans end but I don't know about the F**d rear axle. You may have to get a custom driveshaft fabbed or get a "conversion" u-joint that mixes/matches different u-joint sizes. The 1350 is the beefiest u-joint of the three listed above (wider, larger diameter journals).