The length of the pushrod is directly related to where the oil hole is in the rocker arm. If it is Chrysler oiling, the exact measurement is 9/32nds of an inch of adjuster showing......including the ball, +/-.050. You can tell if the rockers are drilled for Chrysler oiling if the oil hole in the rocker arm is in the bottom thread of the adjuster screw hole. Then you set the adjuster to the correct length out of the bottom of the rocker and measure for pushrod length.


If the oil hole in the rocker is lower than the bottom thread in the adjuster screw, you have to screw the adjuster screw down to line up with the hole in the rocker arm and shorten the pushrod accordingly

You can groove the rocker, groove the shaft, groove the cam, all to let more oil up there but IF the HOLE IN THE ROCKER ARM DOES NOT LINE UP WITH THE HOLE IN THE SHAFT IT WILL NOT WORK. You can force enough oil up to the top to oil the adjusters from splash, but it's still not the right way to do it.