Driveshaft question

[67F250CS]

Swaping from FMX to C-6. I have a 1967 F-250 with 2 peice driveshaft. Got the donors front driveshaft from the bolt on yoke to the carrier bearing. Not really thinking that they would different diameters. I got it home and it is about 3 inches shorter wich fixes the length issue and it slides right on my old back half of the driveshaft. So they mate right up. The question I have is can I use the larger diameter front with the smaller diameter back half? I dont see this being an issue but if anyone has done this and recommends against it I would like any advice for or against this swap of the front driveshaft.
Thanks.

[FORDification]

Hmmmm....I've haven't run into that before, but I don't see why there would be any problem with the two sections having different diameters, as long as they're the correct length and mate up just fine.

[lobuck76]

If it was me, I'd put it in and go. But that's just me.

[67F250CS]

I though it was ok, ITs a FORD afterall. I'll run it ans see what happens.
Thanks much.

[wt4speed#2]

With the shafts being 2 diff diamiters I might recommend taking them and having them match balanced to avoid vibration

Tony B

[willowbilly3]

Just make sure you have them timed or phased right when you slide the 2 together and you should be fine.

[67F250CS]

Thanks, I downloaded the thread that had pictures of the proper phasing. A few weeks ago I think it was. I appreciate the advice.