Who has the best 460 camshaft for gas mileage and towing? Brand and model, what are your experiences with the various grinds that are out there.

Engine is a .040 over 1979 460.
Carburetor will either be 600 or 750 cfm AFB.
Gears are 3.54.
Transmission C-6
Chassis is a 1986 F-350 crew cab
Stock compression and heads. I might be willing to mill the heads; if you guys have noticed significant gains.
I will occasionally be doing heavy towing.