Rear End Gears
OD was a game changer for me and my car!
me too
Just to add, you can usually determine your lowest cruising speed by the vacuum gauge. To do this; slowly rev up your engine in neutral watching the gauge.
If you have a performance cam, you should see the vacuum increase with rpm, up to about 1700 to 2200. In there somewhere, it should plateau, and no longer increase. After 2400 sometime, it might begin to decrease.
Th lowest rpm that the vacuum plateaus is the rpm where your engine first begins to be efficient. That would then be your lowest recommended cruising rpm.
You can cruise lower, but your economy will not be there, as the pistons may still be pushing mixture back up into the intake past the late closing intake
and the headers may be pulling mixture straight across the tops of the pistons on the overlap cycle.
This method depends on the ignition timing to be correct, or at least close to correct. Otherwise the the vacuum will be lower than it should and the peak less pronounced.,
If you have a stock lo-po cam; the idle will be messed up and reading high. and will stay high then begin to fall,lol . So the slower you run it on the hiway the better.
