i never even thought of this before for my 5 speed swap...im running the same purple shaft 284 duration/ 484 lift cam in my 340, and in 5th gear i was planning to cruise at 65mph at 2100 rpm (with 3.91 gears and 28 inch tall tire)...from what i understand, the overdrive will be useless here because my cam isnt in its power range and thus still sucking back lots of gas in order to constantly cruise at that rpm?
