Need help choosing a junkyard engine

cudamark said
The nice thing about the '67 is that it will bolt in without modifications to the crank. You will have to swap the pan and pickup however but you'd have to do that on the '74 engine too. I'd pop the valve cover and make sure you have valve clearence on all the rockers. If the adjustment is too tight, you can get a low reading. You don't have to do a full valve adjustment but just make sure there is some free play on each valve. Any particular reason you can't fire them up? That can sure help on the valve sealing if they've been sitting for a while.

Well the 74 had the key in the ignition but the carb was not bolted down anymore. The 67 seemed ready to go but there wasnt a key. Could somebody give a crash course in hot wiring the 67? I'd really like to hear it run before I take the time to pull it.
What exactly is different between the 67 and 74 cranks? What would I need to do to make the 74 work if I go that route?
I believe I read something about the post 68 heads being slightly better. Is this true? If so should I yank the head off of something else. There is a 1980 road runner with a slant in it as well. would this have a better flowing intake/exhaust manifold or are they all about the same?