How much room for improvement? Help

Just helped a kid put together a H/C/I combo.. Victor Jr Heads, Typhoon Intake, and some oddball SpeedPro Cam (sounds mean?).

Anyways he has 76mm pro m, 30lb injectors, Mac shorties, offroad h-pipe and some oddball 1 chamber muffles with no tail pipes, 3.73s, shortbelt, and really thats about it.. lol

Stock TB, belt driven fan, etc...

He ran a best of a 13.3 @ 103 mph on some pretty tall cheater slicks, 28" tall i think. (had to of hurt him)

What kinda potential is left and what upgrades are going to be most rewarding. I told him he needed to get a bigger TB for sure, and that maybe an intake that was matched up to his heads a little better. Oh and to get it dyno tuned.

Yeah i told him that the 30's might be a little much but he brought up a good point. He's got nitrous already hooked up and would rether run rich instead of possibly leaning out at the end of a run.

And i think a bigger tb would help him out at higher rpms.. meaning bigger mph. I dont know though.. I don't know though.. I skipped the 302 and went straight to the stroker, so what i think works well doesnt always work well on a standard 302.