My Grandfather says the older c175 wasn't that great of an engine. He didn't say why. I am looking at a hough front end loader that has the same engine, but I also have 4 and 6bt engines to replace the c175 if needed. As far as transmission combos available, the bt series has a plate that bolts on the back of the block and you can get ford, chevolet, dodge, and sae transmission bolt patterns. If the c175 flywheel housing comes off the block, you probably could bolt one of these to the back and run any transmission you wanted. What I have found is cummins engines with a lot of use behind a manual transmission, the thrust bearing on the crankshaft is worn and the crank will walk back and forth some. As far as power and rpm, you can turn up the fuel and rpms, but do so at your own risk.