Nitrous and E-85

Are you presently using open or closed chamber heads? It's hard to get good quench on the open chamber heads due to the lack of a quench pad no matter what you do. Some is better than none though, LOL!

If was to do my Ramcharger motor again, the one in my avatar, although I did have the deck milled for zero clearance, I would have went with either the Magnum heads or the Edlebrock Magnum head. Cheaper adjustable valvetrain, oil through push rods and much more quench area. I wouldn't doubt if they flow better too untouched compared to untouched J-Heads.