Well, you may or may not be able to whip him with $4000, but you can get close.
It depends on where you want your power, and your transmission.
If you want your power at 3000-7000 rpm, then the Miniram and a ZZ-X/ZZ-9X cam may be what you should look at (
www.tpis.com) or any of their other cams. (of course that power/rpm range depends on the cam you pick) I would only use this with a stick shift, no automatics. It would also need a lower rear gear for optimum acceleration. (something like 3.73)
note: spinning your stock motor to high rpms is lethal to the bottom end, so i would advise against picking a cam that makes its power over 6K rpm. You would want it rebuilt with forged parts before spinning it that high.
If you want your power from idle to 5500rpm or so, then the Superram may be for you, with the Accel 72419 cam. I want this for my 86. I think its better suited for automatics, but is just as good for 4+3 manuals. (
www.lingenfelter.com for new parts, ebay for used)
I have no personal prejudice against the MR, but i can remember hearing bad things about it once or twice, and ive never once heard of a real serious problem with the SR. If i had the money for 2 vettes, Id do MR on one and SR on the other.
Either manifold is capable of the same numbers.
I would also ditch the stock '128 heads, try to get some 88-91 vette heads. Get them ported and the valvetrain upgraded with stuff for whatever cam you pick. (ESPECIALLY for the miniram!) Things like new springs, Titanium retainers, 1.6 roller rockers, etc.
The best heads you can get are AFR 190s (airflowresearch.com) but they are really expensive and wont get you the bang for the buck that the 88-91 heads will right now.
Youll also need headers at least, Hooker 2149s ceramic-coated from Summit or JEGS. TPiS, or Lingenfelter have a set also of their own designs.