what to look for in donor vehicle

[jlaird]

I'm looking for a running donor vechicle for the engine/trans for my 69. I'm wondering what I should be looking for. I know I want a 350 w/carb, but other than that, I'm kind of clueless. I'm also undecided whether or not to go with man. or auto trans, so what are the preferable trans of each? Is 2bolt vs 4bolt main important? If so, is there any way to tell from the outside? What about heads, year of truck, etc? thanks.