I had done a similar project i had built a 355. Flat tops. Xe262 cam. Air gap. 1 3/4 long tube hedmans. I was running a set of ported 492 humps. Shim gaskets. 3.23 rear end. 4 spd. It was very torquey down low and revved to 5800 or so. I found it was always in the power band at hwy speed. Made it somewhat difficult to drive smoothly. But passibg was a breeze. I switched it up for a set of proheader 64 cc heads. 2.05 valve. 195 cc runner. They were listed at 235 cfm if im correct. It revved to 6500. And was very snappy responce wise but it took all that lowend torque and moved it up in the rpm range. Car is 3750 lbs. On the hwy i will say ot was smooth and very tame but revved to 6500 very quickly and was nasty 3500 and up.. Engine seemed less temperamental in good and bad ways. The camelhumps were better around town and mid range..which is what i do most Maybe due to port velocity? I swapped out to 3.42s and it still seemed the same. We all know the vortec love. But i hate the added machining costs. The valve covers. The different intake cost. The crack happiness. Next is LS.