318-3 Closed Chamber Truck Heads

I have a question on exhaust on these engines. Can I use regular 318 aftermarket headers?
I am trying to get it running better with a little more power to move my RV. I ordered a carb rebuild kit. I have done a full tune up, cap, rotor, points and condenser, plugs and wires.
Please share any tips or tricks.
Thanks!

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You should be able too, yes.