3 inch exhaust with manifolds??

Dunno Rani ! I'm gonna use the stock ex manifolds on my 68 big block GTS. I did use a better intake and carburetor. And I'm using a Howards cam with More ex lift and ex duration to help the exhaust get out better. It should be an ok cam since it has a 112 deg lsa. I too would like to hear some opinions on this.