Quote Originally Posted by techinspector1 View Post
Bottom line: Overdrive trans needs stock or very close to stock cam for the motor to be efficient in the cruise rpm range dictated by the OD trans. I got into an argument with a know-it-all on another forum who was convinced that his 300 degree cam (255 @0.050") was well-suited for use with his 700R4. .
Tech, I have been over this many times and you have nailed it, any performance cam will raise your powerband ( ideal rpm range) over a stock cam, and will be totally ineffecient at 1800-2000 rpms at highway speeds that a OD can add unless you throw in a gear change. I actually saw a guy put a 700r4 behind a mildly built motor and loose fuel mileage! He dropped his rpms down around 1800 and had to step on the gas anytime he went up a slight hill since his powerband had been raised with the performance grind. This is the same reason my blown duel carb'd 32 actually gets pretty decent fuel mileage (I have achieved 16 mpg) turning 2900-3000 rpms at 70 mph with my foot out of it but all bets are off when both carbs are wide open.