Couple of questions:
engine size..??470 big block,bb2plusheads,1050 dom,13.5.1 comp.team-g intake,****y hooker header,700lift roller,
collector size on current headers..??3 1/2
HP level of engine/how radical is it..??it up there
most 396-427 cid. engines perform better on the street with a smaller tube header 1 3/4- 1 7/8.....454 and up can handle the 2" tubes....the really big ones may be able to handle 2 1/4"....the smaller tubes make for better low end torque...I think a 2 1/2" system with a cross over pipe, quality mufflers and stock exit locations is the best for the street. Avoid short dumping under the axle or in front of the rear wheels...the echo and vibration will give you a headache. A stock appearing system with good quality pipes, mufflers and hardware is the way to go. I'm not an expert on all the different muffler choices....but I'm sure the boys can chime in. You may also want to look at a complete system form Pypes....I know several Nova guys who have used their products and are very happy. Some of the catalog companies sell their stuff....good luck.
wilma