Port my own heads?

Just as a side note, I have a 70 swinger with a 360 in it. Here is some background on it. 367 c.i. stock crank, rods, block. 11.11 to 1 compression JE pistons. Ported X heads by me with 2.02 1.60 valves. A solid flat tappet .540 lift 255 @ .050. Torker intake with a 750 dp holley, 1 5/8 headers 2.5 inch mandrel exhaust dumps at the rear axle. 904 low gear with 4.56 rear gear. My car was just like g-ma had it, with PS and column shift, steel wheels, and all steel. It weighed 3240 with me in it. It went a best of 11.68 at 116mph. I tried bigger TTI step headers and 3 inch exhaust and it did not run any faster even after exhaustive tuning. I also tried an 850 before and after the exhaust work with no gain. My point is at this level the exhaust and carb were right. Once you complete the head work your motor should make more power than mine and may react differently to exhaust. Every combo reacts different to different things. Good luck and dont be afraid to try new things.