I have a older "running" small block chevy engine that I think could be used as-is for driving and crusing NOT RACING. but i'd like to freshen it up. My question is.... If I go and change the timing chain and gaskets..... can I change the rings and bearings without having to go and get machine work done on the block and crank? or just run it till it NEEDS to be rebuilt? its a little tired but runs ok........ Im workin with a budget so I cant just run out and buy a crate motor or get a premium rebuild. what do you think?