I'm pretty sure that the 284 is too big for your engine in terms of making best power but based on your testing it might be a good match for your chassis. In other words, if you put a smaller cam in it then perhaps the extra torque will set off a domino effect and it might take you a bunch of work with springs and shocks to get back to a good 60 ft time. Same thing with your timing test. I'd never recommend adding timing like that to solve a reaction time issue but if it works for you then go for it. Seems like playing with fire though. That is a lot of timing for a high compression wedge headed engine. I'd never run 40 degrees of timing in a high compression BB Mopar engine.