Magnum 360 rebuild help
Just do the obvious, compression check and document the numbers. If that checks out good, check and change what seals and gaskets have been obviously seeping, maybe a fresh performance water pump (a good radiator upgrade is not a bad idea either, small engine compartment, thin casting magnum heads), quality timing chain upgrade, intake, headers, if I was planning on a cam I would go ahead and do it while I had it out. It's easier to check for coil bind and other issues and change springs (if your grind requires it) if it's on an engine stand. Ignition upgrade, distributor recurve. Like xLurkxDogx said, at 70,000 miles the internals are going to be fine, the incidentals I would do because it probably has sat more than been ran. Check your oil pan gaskets and crank seals, you don't want to have to change those in the car.