Since your there put in a cam. I'd get a 3-angle valve job first, with crane springs because the stock ones can float at high rpms.
A built t-5 can only handle 330TQ. Not worth the time and money get a tko.
I have a 95 gt that I'm add mach 460 too. My problem is that the rear amp wiring that goes from the amps throw the side panel and under the rear...