I don't think you can go wrong with the 85 Chevy. I am running one, bought mine three years ago with 230,000 miles on it. Put another 3,000 getting it back up east. That is about the limit on a 305, and the th350c transmission was just about at it's end.
I installed an almost new 350 engine and had the transmission rebuilt, have traveled west twice with it and still runs well. I would rather have found a 305 engine, for the mpg's, but the 350 gives me the power I need if I carry a lot.
You do have to take care of the front end, mine was well taken care of. But this summer I installed a new idler arm and inner and outer control arms, not a big deal.
I prefer this age vehicle because of the lack of computer control, at least I can work on this one.