Considering a 5 speed swap

[rcbildr]

I'm using my 1960 GMC as my daily driver now and would really like to have a 5 speed in my truck...my commute is 35 miles one way and I could really use an OD transmission to help with the fuel mileage.

I have two options sitting in my shop right now, one is a T5 out of a V6 Camaro and the other is an NV-3500 that came out of a 2wd Chevy truck. The only towing I have really planned for the truck is my 26ft Airstream that weighs just under 4000lbs (according to the factory owners manual).

My GMC has the 305 V6 and most of the information I've seen for the T5 swap is for putting it behind a Chevy engine. I figure the only real difference would be trying to get the clutch to bolt up to the flywheel.

My questions are:

Which transmission would be best to use?

If I use the T5, is there any info on putting it behind the V6?

Is there an adapter plate available to put the NV-3500 behind the V6?

I'm thinking the T5 would be the easiest to use on my GMC because the NV-3500 has the integrated bellhousing....not a big deal there because I can use that transmission in my 67 suburban. Any help/thoughts/info would be greatly appreciated. Thanks!