Chevy s10

put the S-10 body on the the cut full size frame , that'd be easier , and hang on

Yes, a small block V8 will fit. The problem is there is a large amount of work required when you replace a different size engine in a vehicle. Motor mounts, exhaust system, transmission, emissions, gauges, wiring, etc. All of this needs to be figured out. If you are paying a garage to figure all this out, it will be a very expensive endeavor.

Yes it will be an endeavor indeed. I've seen people put V8's in old Vdubs so you can certainly fabricate your truck to do so as well but as Gary mentioned, it's going to be a big job.