I have a 67 gs400 ,matching numbers 400, St 400 and 10bolt 2.93 gears considering fitting stage 1 455 from 71 rib with small cam a little head porting 10.1 piston 800 quad and hei dizzy, maybe 425 horse probably less, how will the stock tyranny ,( with stock rebuild ,as it has never been touched ), and the 10 Bolt feel about these changes? Are the up to the task?