Those figures are right in line with what I dynoed a late G at that was overhauled and the only modification was to install gas alum. pistons. Nothing wild just so it would still run on cheap pump gas.
And as to the gas verses all-fuel when stock on my 1946 A as I was in the middle of the field plowing I switched from gas to kerosene or vice versa ? and the only differance I could tell was the smell of the exhaust.
And just for curiosity on my 1945 B which was upgraded to .045 over JD cast iron gas pistons I tried kerosene in it. When first switched it seemed to sit there and run fine,but the slightest load like trying to move or move up a very slight slope and the KNOCKING came on strong ! I didn't do that for long ! and don't recommend any one else try it !!!!