Bob- I don't know your financial situation, but personally, I wouldn't even fool with the 6V-53N. It has only 210hp and 424lb/ft torque (about like a big block chevy). I think you'll find it to be painfully slow up the hills and with only a 60mph top speed, a bit on the frustrating side. Even if you turbocharge and air to air aftercool the engine, you might get about 300hp and 600lb/ft torque. Not quite the same as if you found a donor bus with a 6V-92TA and HT740 or B500 Allison. 350hp and 1100lb/ft torque is quite different. There are other engine/transmission you could use. Let me know if you're thinking about swapping out. Good Luck, TomC