I've read a bit on how boring over doesn't do much. For every little bit of displacement you add, your adding more friction surface with bigger rings or what not. Again, just somethi ng I read.

Not trying to argue, but milling the head to increase compression won't work as you offset the timing chain. The thinner the head, the more off your valve timing is, hence you didn't really feel a difference. With an adjustable cam gear you can degree in your cam and see some actual performance gain s. I feel its even documented in the fsm. Same goes for a cam, if you dont degree it there's not going to be a real gain.

Correct me if I'm wrong, but running the Aussie cam doesn't increase output, it just lets you run roller rockers and mechanical valve train, hence a more responsive engine. Its when you get it with the actual aussie head that flows more air that you gain power. My buddy has an aussie head, cool mod, but the gains are minor, so its only worth it as part of a no cost spared performance build. Plus they are like $500 and about as easy to track down as 4.875s.