After doing some research, and a lot of testing, I have successfully done conversions on the upD858 AM/SSB and MB8179 AM/SSB chassis.
For these conversions, I used IRF520N's from International Rectifier. I'm sure you could substitute ERF2030's if you wanted to do so.
For the upD858 chassis (President Washington, Madison, Grant, Cobra 138XLR, 139XLR, etc):
Parts you will need:
IRF520 (or ERF2030)
EKL companion part EN-369FN (You can build your own, too)
56K ohm 1/2 watt resistor
39pf...
MOSFET conversions for upD858 and MB8719 boards
For these conversions, I used IRF520N's from International Rectifier. I'm sure you could substitute ERF2030's if you wanted to do so.
For the upD858 chassis (President Washington, Madison, Grant, Cobra 138XLR, 139XLR, etc):
Parts you will need:
IRF520 (or ERF2030)
EKL companion part EN-369FN (You can build your own, too)
56K ohm 1/2 watt resistor
39pf...
MOSFET conversions for upD858 and MB8719 boards