So who's running a Comp XE268?!

I just got my 68 Dart 340 Ragtop on the road and not happy with the performance. Cam unknown but thought to be stock 68 340 4spd cam.(should have changed it) Stock freshened bottom end. Motor 20 over KB hypers, around 10:5 to 1 160 PSI cranking compression. Eddy closed chamber,Eddy 600 carb, stock manifolds,4 speed 323 rear ,2" exhaust. 15" rear tire 14" front. Motor ran better when tired. No A/F gauge but have to keep half choked till warm. Would New Eddy heads from stock X heads make that much difference with Carb ? Thinking maybe this cam could help and maybe see better mileage. I know Cam tech. has come a long way. Street cruiser no track.
Don't want to give up on it yet will maybe try re-jetting but not too familiar with Eddy carbs .I saw this thread and figured I'd throw it out there in case I do change it.
I try and do everything myself so yes I stumble along the way.