Originally Posted by Kebowers

for a '300' head --replacing the valve stem seals is an 'on the car' job about $300 max..

DO NOT RESURFACE THE HEAD. That is a fatal mistake. The 'warpage' spec are generous as the head is quite flexible. I think it allows over 0.030" warpage end to end (and really a lot more--up to 0.060 is OK.) If you 'resurface' the engine side, then when its tightened down, the camshaft side is no longer straight and the cam will ruin the cam tower bearing surface and cam journal, and seize, or break the timing chain,--usually total engine destruction.

To properly resurface that head, the valve guides, cam tower locating pins, and everything else and core plugs on top have to be removed and BOTH sides of the head milled in a planer to ensure the resulting surfaces are exactly parallel. Alternative is a trial and error fitting of shims under each cam tower to restore exactly even height (straight cam). That is a VERY time consuming task, but can be done and will certainly work. The head has to be torqued down (less the cam towers) and then one tower at a time tightened to identify the 'high' one--and by how much. Then shims added under the other towers-one at a time until the cam turns freely in the bearings.