That will make a GREAT engine for your truck! Lots of guys have done them...just the basics like many other swaps is all you need.
Join this site (or at least snoop around a bit) & you will get your answers.
http://caddy500.com/. There is a "Truck" section of guys that have done the swap.
A fellow I know from another site just finished a big Caddy swap into a '79 or so truck, his name is Jon Volk...he is a member here, but only posted a couple times. He has an E-mail address listed here & may be of some help.
Do it! Let us know how it goes. Lorne