reworking stock heads or buy aftermarket?

the exhaust valves hit the pistons, do not just throw on a new pair of heads. .010 over is unbelievable, that will require +.010 pistons and +.010 rings , what size bore and stroke and cam are we talking? common oversize is +.020, +.030, +.040, and +.060. a ton of slop in the timing set retards the cam-exhaust valves closer to pistons, measure the cams lift