My 48 Loadmaster has a newer 235 (1960) and it runs great, will cruse at 45-50 mph no problem, it has a 2 speed rear, 6.13 high-8.10 low, would like to get another 10 or maybe 15 mph out of it by changing transmissions if possible. Would prefer a bolt in operation. Also want to consider an automatic trans, that would handle a 12000-14000 lb. load. My plan is to take the grain box off,and build a tiny house on it. Help ! and Thanks.