Generation IV External Engine - Drilling for rear steam pipes

I didnt realize the rear ports are plugged on LS3 heads, and i put them on backwards. So i need to drill the out the plugs and run front and rear. I'm simply going to drill them out and run a hose around from the back. How many people have done this?

I drilled them out on my ls7 heads... because they were plugged in the rear.. no issues, I tapped mine afterwards and used screw in fittings.

I'll just run a pair of duals and join them with a T, or just find a quad LS1 pipe.