Smog Port Hole/Header Problem

I had the same problem whan I put a 360 into my '63 Dart and didn't realise the early manifolds don't cover the smog holes. As I didn't have any taps and didn't want to pull the car apart I just used some big self tapping screws and wound them in - the cast iron's pretty soft - it worked fine. Not the right way to do it but easy and effective.