All for .370 lift and under ........

teringer said

I had a gm that keep getting better milage in a heavy truck 305 cu in it with a over drive trans up near 30 miles per gallon about 6 months later I found out why it got so much better / it started popping thru the carb at light throttle yes the cam was wiped every lobe was rounded off evenly like it was made that way so go low lift and you will be there. find some 1.4 rockers

Click to expand...

I believe it was Crower had some mileage cams years ago. They closed the intake valve late so at low RPM cruise it was pushing air and fuel back out into the intake manifold. What this did was a couple of things. Vaccum was low and essentially the intake stroke took in say 75% of the air by the time the intake valve closed. So on a 300CID engine it drew in the equivalent of a 225CID engine. But on the power stroke, it made use of the volume of the 300CID engine. Basically Aitkinson Cycle. When you get the engine reved up, intake inertia continues to fill the cylinder longer, providing more power.