When good is not enough, Camshaft time again.
I would look into a hydraulic roller setup utilizing comp Evo lifters. I'm not 100% sure what folks are getting away with concerning valve spring pressure. I owned a stock stroke 440 with a hydraulic roller cam (unknown specs) and was impressed with it's manners and power output. This would be a viable low maintenance option.
If you put a bar in it definitely gap the rings for nitrous!!