I skipped over a bunch of posts so i may be just restateing. The bottom end is good to about 6k no problem. Its the top end that is going to have troubls if it is stock. If its all stock your going to run out of power about 5k so there isnt a point going past that. I probobly wouldnt worry about floating a valve till 5700 or more though. If you have a larger cam and better springs, wind that baby up. 289s love rpm. I shift mine at about 7100.