smitty3215 has the right idea. Buy a entire doner truck. That way you can pull everything you may need including fan, radiator, alternator, ac compressor, etc. If you get a truck with the transmission you want also, then that will save you money adapting things. Once you have taken everything you want off the truck, part out the rest and scrap the metal. If you play your cards right, you will have a conversion set up for not that much $$$.
I am still working on finding a doner truck myself. I let a 1996 with 150K miles and a 5 speed slip away a month or so ago. OOops! Spent my money on the axle
Now I have to build up the piggy bank again.