Exhaust manifold ?

Hi all, I've got a question regarding exhaust manifolds on my Dart. Would the larger 340 hi-po manifolds kill the bottom end with my 273? I'll be running an Edelbrock performer intake (small runner), 302 heads w 1.88/1.60 valves, intake port matched, mildly ported. Cam is a Comp Cams XE256H, .447/.455 lift. The car currently has dual 2" pipes with the stock 273 exhaust manifolds.

Thanks