Well I ordered myself some new valve seat cutters

pittsburghracer said
These are pretty much made to be used by hand. A few turns by hand and it’s cut. My mind isn’t made up on these as shortly after I bought a valve and seat machine. About the only one I use is the 70 degree cutter on my speedmaster or Edelbrock exhaust

Thanks for getting back. I have some 516 heads that I want to try and use cutters to inlarge the exhaust from 1.60 to 1.74.

I have stones but that seems a lot to open up with grinding.