I rebuilt my motor about a month ago and made it a 421 from Wicked. I mostly ride trails but i also like to drag my buddys on there 450s. If i try to drag race i start in 2nd and can get it into 3rd gear but it wont go into 4th or 5th if I have it pined, you really have to let out on it to get it to go into 4th. I have been reading posts that higher HP engines need to make there tranny a OVERRIDE TRANS. Is this true or is there somthing else i can do or buy that would help my shifting problem better?