[hoss2006]

I'm looking to get a grizzly g0704 mill and convert it to CNC. Grizzly.com has this retrofit kit: https://www.grizzly.com/products/Min...r-G0704/T25436, which looks like all of the electronics needed. Then CNCFusion.com has this kit: CNC Fusion, which looks like just the ball screws. Will I need both kits or just the Grizzly kit?

You have more options you can consider, there are more conversion kit options out there, check my main page under CNC Kits and Plans. g0704.com
Also several tried and true options for the G0704 electronics.
The grizzly/flashcut packages main plus is the flashcut electronics and control software, Dave Decaussin formerly of Fadal raves about it.
You can get as good or better performance from the more affordable packages IMO.
Hoss