Pushrod clearance for 1.6 rockers on iron heads

Quick question about pushrod clearance, as the non availability of Comp custom grind cams has me in a bind and trying to cover all future possibilities.

Iron heads, under .500 lift, roller tip cast steel self guiding rockers, stock pushrod diameter. Would going to a 1.6 ratio in the future require slotting the pushrod holes in these heads. About the only cam I can get is a gen 1 with a pretty odd profile that might need a bit of help in the future if it doesn't work out well, and 1.6 rockers might help and are easy compared to a cam change in the car.