How much power are you going to make? There are thousands of modified and stock 440 blocks out there turning over 6000 rpm. Are they ideal? No. Do they work? In most cases yes. You dropped a valve, this was not an oiling issue. Can it be sleeved? Maybe it could be saved. Maybe your power level dictates a better block. I've had engines with both factory and aftermarket blocks. I broke a factory one but it wasn't a oiling system failure. Most RB block failures I've seen were not oiling related, but structural.
Doug