I'm getting ready to start building a generator setup.I like the setup ventrac has but I can easily build my own to my tastes,I'm going to use a heavy,cast iron cheap 1800rpm 4 pole generator,either a 7 or 10 k unit,and with my 31 hp I can pulley it with an 8 inch pulley,should get me 60 hz,and 120v at 2100 engine rpm.looking at the power curve, this requires 13hp to fully run a 7 k .my average load is around 1200 watts and I'm running thru a 30 amp breaker ,so my peak load will be around 7200 watts,irregardless of the size I choose.The ventrac setup requires you to spin the engine at 3600 rpm,which is unnecessary for the 7200 watts I require...I'll save a ton of fuel,noise and a little engine life at 2100 rpm..of course i may have to adjust the pulley size to keep a stable rpm but I'm confident I can run way lower than 3600 rpm and maintain stable voltage and frequency.