SM Head Modifications on a budget

Have we reached a point where the thinking is that the 285-290 number isn’t going to materialize by employing simple diyer friendly mods?
Personally I think that number is not possible until the apex gets widened. I want to try different valve jobs as well. Trying to think through how that could be accomplished without using up 3-4 ports in a head. I think in the 270s are possible, especially if we start relieving the chamber a little. But then we're going to step 6. I'm not ready to leave 1-5 yet.