Depending on the length and GVWR, I don't know if I would go small-block. A shorter model (5-6 window) might be okay with a 350, but anything larger and I think I'd want a big-block.
I had suggested a big-block gas swap to another member here that felt their 8.2 Detroit was dangerously slow. My old man happens to have an '83 Pace Arrow with a perfectly good 454 big-block that runs great and drove fine, but the roof has gone bad and he'd like to sell it for $1500 for parts. 65k miles. The other member seems to have decided to stick with what they have for now, presumably until they have a better budget.
It has been verified as having the TH-475 (10,000 lb GVWR) and according to research, would do the job in an appropriately-sized bus. Pickups / SUVs of this model year were rated at 230 hp / 360 ft/lb with this engine, and motorhomes got a slightly more powerful setup. Depending on GVWR, it may be perfectly fine as-is, but 275-300 hp and 400 ft/lb of torque are completely doable with a few upgrades like a larger carb or beefier cam before installation. If you're close to or in Virginia and are interested, shoot me a PM. You can hear it run before making a decision.
"CHEESE WAGON" <email@example.com> Suggested reading: (5 threads)