Thought I'd chime in on this post too. If you're considering going v8, auto, etc it can very easily snowball out of your control. My last project did this. I had v8, 400 turbo, camaro rear, ifs, etc. It seemed every time I went to the next step serious fabrication and modification was required because of the "updates" I had installed. Because of this (and the boatload of $$) I lost interest in my truck and sold. It was frustrating.
Now I'm not saying that restoring these old trucks isn't frustrating but I believe now that a person can mitigate how much frustration they experience. If you're paying a shop to do the modifications you may not be as frustrated (perhaps your wallet), but if you're doing it yourself make sure you know what you're doing.

I have begun a new project (2 actually) and I have been converted back towards the restore side. (Well maybe not pure restore) I have a PLAN. HAVE A PLAN!! STICK TO IT!!
Don't get in over your head. Enjoy the truck now if you can. Many people tear into decent trucks and never get to enjoy them before the work begins. I know from experience!