Based on your opening question and some of your responses I think we need to know your budget, and your expectation. Certainly you can put headers on the car for far less than $2000. I also think that that a different cam will put more power in it too.

Your car/motor seems to run about right for what it is, and making any one change will not likely yield a huge gain.

Are you running your current combo on pump gas? If so, this surprises me. What is you cranking cylinder pressure?

If you go to a cam swap, I would go with a small solid

Currently yes I only use pump gas but it tends to knock on 91 octane so I pretty much only run it on 94 which I have easy access to.
If I go the headers route I will also swap the cam since I think it makes sense to maximize the benefits of it.
It's not so much a budget issue as much as cost per benefit, 2k just seems like a lot for an exhaust swap. The exhaust I have now is all original so I kind of like it as is. My hope was to gain 30hp without switching out my current exhaust but that may be unrealistic.

While a TTI header setup would be nice,there are plenty of good A-body header choices with a lesser price point. Especially for a street based engine.I think a t102 mph you should be in the high 12 second range.Chassis as mentioned or gearing change??What transmission do you have?

You don't need headers to make power. Will you (usually) make more power with headers and exhaust? Yes. Do you need the difference? In street driving, usually not. I have one of each, both are stroker 340's, 422 and 426 cubes respectively. Both are built very similarly, similar cams ported iron heads that flow at around 280, both in 71 A-body cars with manual transmissions and 3,91 gears. Both have both been dyno'd so I have real data on them. The 426 cam specs are attached, the 422 was a very similar grind. The 426 made 450hp and 500tq. These numbers were made with exhaust manifolds, stock iron intake, stock Thermoquad carb, and everything else externally stock down to the belts and hoses. Now, the 422. It has TTI headers, mandrel bent 3" exhaust, a single plane intake, a Holly 950HP carb, 7AL ignition, and all the other 10 cent tricks. It made 530hp and 520tq on the dyno.

So, bottom line, A LOT of $ and optional equipment (as a package that works well together) resulted in roughly 75hp and 20lbs of tq most things being equal if not at least similar.

On the street you simply don't need the extra hp. the 450 engine will blaze the tires at any speed and torque is so close it feels the same.

.02

I am building a mild 360 now for a daily Duster.. well nice days but to drive it a lot. 4 speed. 3.55 gears. I am really really wanting to use manifolds. I hate headers for street cars. Care to shine some light on which manifolds? With a mild cam, rpm performer intake, and smog 360 heads, think 325 hp is possible on pump gas?

With a mild cam, rpm performer intake, and smog 360 heads, think 325 hp is possible on pump gas?

Yea, my point about pushing a stroker is two fold, nothing beats torque around town no matter how much peak HP your engine makes, and I've yet to hear anyone say:

"I sure wish I would have just built a stock stroke engine" after driving a stroker

I'd think a well tuned, nearly stock 340 would be around 350 ponies.