89 5.0 heads and stuff

[USMC302]

Biggest problem.....hooking with street tires when you get a blower, lol. IMO I would go with the TF heads and X303 cam you mentioned, you will be ok with piston to valve clearance with that setup, but that is the max I would push without valve reliefs on teh pistons for those type of heads. The transmission will be fine as long as the street tires are spinning, once you start hooking hard with the right suspension, then you will start throwing trannies. I actually ran my stock T5 at 11.20's @ 125 and it's still a good tranny, no problems at all, I just pulled it because I'm going with a racing auto. You can still run the Trickflow heads and cam with a blower and be very streetable, but as you mentioned, you might want to step down on the gears with that setup. Good luck.