Sure a Logan guru will be along shortly.thinking you'll have to change lead screw also unless yours is slotted .dont think it is.also you would need cross slide besides apron. 820 has gearbox best I remember.you would need it too to go with lead screw off 820.not sure if banjo is same on both..good luck..be a nice upgrade..
the screw on the 700 is slotted. was hoping to use the lead screw off the 700 just change the apron and possibly the cross slide. my 700 doesn't have a gear box its change gear.. anyhow looks like the 820 parts I had found fell thru so its just a pipe dream again