You can overhaul just the bottom end for fairly cheaply. I'm guessing $200 or less in parts plus your time.
Pull the crank and have it turned, and replace the rod and main bearings, rear main seal, timing cover gasket and crank seal, timing gear set and oil pan gasket. Don't forget to check to #3 rod and replace it or have it reconditioned if necessary. If you have to pull that rod then you are talking about a head gasket, valve cover gasket and intake/exhaust set too, so you might as well replace the rings if you've got to go that far.
You can get a re-ring kit with main bearings for $190 from Chevs of the 40s and I think that includes gaskets, bearings, main bearing, rings, seals, etc...
Patrick's has rod bearings for $50, mains for $130, gasket set for $70 and the timing gear set for $32 They also have packages but the prices aren't on their webpage.
An v-8 engine swap might not be too much more if you install a running used engine and start saving to re-build it later.
