Help on rebuilding a 73 340

First let me say I am 67 years old a retired farmer pretty fair diesel mechanic , welder, electrician but as to tuning still trying to learn my 318 with the 3.55 gears is slow off the line but works well at higher speeds....but just trying to figure out what would be a good cam choice so that it will idle yet have some good juice in the lower end. I really am not concerned about the best milage but hate to waste fuel, not into racing but enjoy having some hp when you want to romp on it. I have plenty of free time but hate to waste it by doing the same job twice. In my area the speed limit is usually 65-70 most places I drive which was why I used the 3.55 gears. So I really appreciate all the input from all of you not quite sure how to do the thank you on this but THANK YOU ALL FOR THE ADVICE IT IS GREATLY APPRECIATED