You might also want to look for a "donor" vehicle for parts for your truck. I have a 1955 series 1 into which I am putting a SBC. I watched the ads, went online, etc., but always felt that I could do better cost-wise. After not too long, I found a 1967 Chevy Biscayne. It had a 327 with "double hump" heads. The whole car cost $500 and I would have been happy with that price just to get the engine. It also, however, had a Muncie 4 speed. The engine, transmission, carb and rear end from the Biscayne are now in my truck. The drive shaft will have to be modified but it will go in the truck as well and I'm hoping that the steering column will work too. I did rebuild the engine but overall, it was a very good deal for $500!
Be patient - if you miss one deal another will turn up...