Pushrod length?

You get maximum valve lift when the rocker is tangent to the valve at max lift
If you do this then the geometry is off about as far as it can get valve closed off the seat
you need to split the difference
set the rocker tangent to the valve at half lift
tangent to the valve is from the center of the shaft or fulcurm to the center of the tip roller or to the top of the valvestem with Iron on stock rockers
you want the NARROWEST sweep across the valve tip
you get more area under the curve this way and your rocker is not going up at a big angle with the valve closed
when you roll the motor over the rocker should tip down at tdc about as much as it tipps up on the seat
when in the middle then measure your pushrod