What is the speed of a 51 case DC in first gear. I believe it to be around 2.1 mph. I would like 1.7mph with full throttle (any one have a way to modify?) . Have an old pull grape harvester that I would like to use with the DC. It needs about 49 pto power. I am planning to put in new 4 1/6 sleeves and dome pistons to get the power in that range.