Magnum heads. Is it safe?

I have just installed my new roller rocker system in the magnum headed 360. Although all of the pushrods are close to the head casting. One is touching the casting. I am wondering if it is safe to grind a little of the head casting off to let the pushrod clear the head? This would be the backside of the intake face. It is about 1/4 inch thick and close to the #4 intake runner. I am only looking at taking a few thousands off. +/- .005

So what do you think? Is it safe?

Jack