I had a 350 in my nova and put in hooker comp headers with 3 in collectors and a 2.5 in exhaust system running dual 40 series flowmasters. This setup worked great for me, however i am now puttin in a 383 stroker and will be upgrading to 3in exhaust with turndown straight outta the mufflers for the most flow. I would say go with the 3 in exhaust and some good flowin mufflers and you will have much better flow and plenty of room if you decide to make more power. (dont we all?!!)