Get the block inspected, crack tested, bored if necessary, honed etc. Your machinist will tell you if it's usable.



You can buy rebuild kits on ebay. Items like this VRS kit will help:

http://www.ebay.com.au/itm/HONDA-CRX...#ht_1036wt_905

And you can get the piston rings from companies like Hastings



To rebuild at home will require a good set of tools. The cleaning (block, head and internals etc), inspection (all parts), measuring (cylinders, bearings, ring landings etc), and preparation (decking, boring, honing, crack testing, balancing etc) should all be done professionally but if you're prepared to research, take your sweet time and stuff up along the way (inevitable for a first time IMO) then it would be a great project.

You will need a lot of sockets and wrenches, power tools (drill, compressor/gun etc), screw drivers, valve spring remover, piston ring compressor, cylinder honing drill bit, micrometer, feeler gauge, assembly lube, a proper parts-cleaning setup, etc etc. It can be done but it's best if you have an experienced hand watching over your shoulder I reckon.