318 with Edelbrok perfomer intake and 600 cfm 4 barrel, what headers please?

IF looking what the next mod that would give the most bang for the dollar probably would be a cam.
I agree with 273. A cam with 204* / 214* duration at 0.050" would be a nice addition. There's a lot of cams out there that will help the performance even with stock exhaust manifolds. Don't get me wrong here, there's nothing wrong with going with headers but would the cost justify the small increase in power and torque. True, they would be good later on if you have plans on going with better heads, bigger cam and carburetor. I think that a small cam, curve kit, gears and a stall converter would make a difference as well. If you're gonna use the car as a daily driver and just want a bump in performance I'm not sure that headers would be worth the extra expense.