American Motors: Exhaust system 4 max torque, hot rodder, crossover pipe

Question
QUESTION: I've got a J10 with rebuilt 60 over 360. Runs great now w/500 2bbl and stock iron exhaust and crossover pipe into a Flowmaster type muffler and single pipe out the back. It has a 5-speed stick, 410's and 33x12.50's. Q: Are my stock iron manifolds the best $$ for torque option or would aftermarket headers be worth the investment? If headers are worth it, 4 tube, shorties, or 4-2-1's.  Thanks.

ANSWER: The longer hedders will give you more torque, but with the layout underneath, you might consider using the shorty hedders. The difference between the two with your modifications will be minimal. Keep the pipe diameter large if you only have one tailpipe.
What cam are you using? That can really affect torque.

---------- FOLLOW-UP ----------

QUESTION: I don't know about the cam specifically. As an old hot-rodder, I know the cam is close to stock as it idles smoothly and has plenty of "pull" at low RPM. As to the headers; I'm hearing you say that if I went to the longer tube header with say a 2.5" free flowing exhaust and free flowing muffler out the back, I would enhance the torque? Correct me if I'm wrong...my goal is reasonable mods to gain torque/mileage. Would the above header/exhaust combo produce significant torque over stock iron manifolds w/a new free flowing system out the back? Thanks again.

Answer
Anything you do to reduce the backpressure created by the stock exhaust will increase the torque AND horsepower.
I don't know what you consider "significant", but there would be a good increase by applying the modifications you listed.
HOWEVER, a stock engine's torque AND horsepower is limited due to it's design and current inside components. One of the best way to increase your torque and horsepower is to install the correct camshaft as it has one of the most dramatic effects on the engine producing torque.
You would also increase the engine's efficiency by replacing the gigantic 500 two barrel with a 600 cfm 4 barrel. Though you have a 500cfm carburetor, air flows better through 4 smaller venturis than two large ones. That along with an aluminum dual runner intake manifold would also contribute to more torque.