Baldy,
Yes, I have tried shorter pushrods. I actually shortened mine 1/8". I still broke a rocker. I also bought the next shorter pushrod for a 216 but it was about 1" too short.All this together makes us think that the head may be milled too much.

Scootin thru with a 52,
Good, Economic and Classic
1952 Chevy 1/2-Ton