Quote:

would you still recommend a 2,5" exhaust it you change the carb, intake, aftermarket cam and headers? or would u step up to a 3"?



I wouldn't. My car had factory manifolds and a 3" system when i bought it, 70 440 'Cuda. Louder than hell, massive drone.
Yarded the system and sold it. Installed headers and a custom 2.5" system. Not mandrel bent but nice (a good pipe bender knows how to bend pipe without overly necking it down.).
Very nice sound now, more power and no drone.
IMO 3" systems are far more likely to drone than 2.5"

And I'll go to a GOOD exhaust shop any day. All cars are different, I want my systems "high, tight, and even" It takes a good exhaust man to do that on MY car! Not a system meant for every other 440 Cuda out there. Thats my 4 cents.