What is it in, a ranger? I would say 2400 would be the min I would go, myself would proabably put a good 10" converter in it that would be about 3000. I would keep the 4.88's unless you are gonna drive it on the hwy. a bunch.
I would probably ditch the C6 and put a built C4 in it.
What do you have for a dist.? If you can get your advance in quicker it will probably help it run better as well.
Cheap Thrills Off Road
2003 F-250 4X4 7.3 PSD Crew Cab