The 010 block is a widely used generic block.....trucks, cars, muscle cars etc. If you would google that number and the head casting number you will find all the info you need. As far as a balanced rot. assembly it all depends on what you want to use it for.
If your engine is worn out and needs a complete build then yes buy a GOOD rotating assembly or use your crank and rods if you can......then whichever you use take it to a GOOD balancing shop and have them do the balancing. I would never buy a supposed "balanced" rot. assembly and take their word for it, also they don't have your flywheel/ flexplate or harmonic damper to balance to the new parts. I paid $175 to get my 507" Cadillac balanced to within 1/2 gram....well worth the peace of mind.