I'm considering pressurizing the rocker shafts on  my '55 292. I know there are at least a couple of methods, pinching off the shaft drain tubes appearing to be the easiest. My concern is about possibly starving some other part of the engine for oil. It looks like the output of the passenger side shaft goes to the timing chain. I don't know where the oil from the driver side tube goes, distributor/oil pump drive gear maybe...? I'm pretty sure a few guys here have done this so I'd like to know what method you used and the results before I pull the trigger. TIA for any advice.

I think it's wise to go with hardened exhaust valve seats while the engine is being rebuilt. I know that "G" heads can crack between seats, but I have no direct knowledge of that occurring while installing hardened seats. I suppose it has much to do with the condition of the heads and who is doing the work. Having to baby it while driving can be stressful and takes the fun out of the experience. If in doubt, ask the man who knows. His name is Ted.