So what will probably break when HP rises?

68 fish, currently 340 (maybe 350 HP but who knows?), 904, 8 3/4 3.91 SG. Indestructable with 245 M&H slicks and 255/60 street tires. Going to put a set of M&H 275/60 drag radials. I am also going to slip in a 500 hp / 500 ft-lb SB and run it down the track as well as local street.

What should I expect to be the weak point(s)? What should I be beefing up next?