my less than 2 cents...
I didn't catch where you were trying to stay around, but may I offer a few suggstions from my experience with this same thing.
Preface: I'm not all familiar after 80 how the computer did everything, so what I say might not apply correctly. My apologies in advance if that's the case...
1) Better breathing up front means more exhaust opening. And the reverse is true. If you are going to open up your exhaust, open up your intake. Drop the snorkel air intake setup and go to a open-element K&N. Also, your original Q-Jet was a 750cfm carb. Better breathing requires more fuel. You may be limiting yourself with the Holley 600.
2) If you are thinking about dropping money on heads and whatnot (the top half), be sure your bottom half is up the the task. From what I recall, a decent set of heads is gonna run you about $1K. If you're gonna do heads, might as well do the bottom. But if not, Edlebrock has a nice Performace Package that included heads, manifold, and I think the carb. Spec'd on the 350ci was somewhere in the neighborhood of 300+ hp. Summit Racing has the specs...
3) for all the rigamarole that you may go through doing all this aftermarket to your engine, by the time it's all said and done, it's really hard to beat just buying a brand new ZZ4 crate engine from GM with 0 miles on it. Then you're talking 355hp, 405lb/ft torque. And it's ALL NEW! Just drop it in and go play in traffic! Plus, you'll have a backup 350 to do what you want with. Sell it, keep it, do whatever. If you sell it, you apply that to the cost of the ZZ4 engine and you just saved yourself some more bucks. Also, the ZZ4, as great as it is, still has plenty of upgrade potential for down the road. I got mine for about $3300 delivered fresh in the crate to a dealer for me. Ya drop it in and ya go. No muss, no fuss, and very few people chuckling anymore at your engine ratings
4) Ignition system. Skip the chip. The claims of ANY chip mfg is only after everything else has been done to the car. Check any car forum for that same info. Everyone seems stuck on MSD ignitions. Personally, I prefer Jacobs. I believe they were around first and IMHO, have a much better product. They also GUARANTEE their increases. I'm a believer.
I did my car in the order: Air intake, exhaust, ignition, engine, March pulleys (aesthetic -vs- performance? ehhh...)
