Be aware that cat motors are set up for specific usage, you cannot use one set up from a generator and then into a road engine, not without changing most internals such as the cam and injection pump. I had a similar problem with a 3306, i had another motor but it was used as an oilfield hydraulic pump, all its hp and torque was at a specific rpm. I just rebuilt that 3306 last month, its in one of my 1992 Peterbilt concrete mixers.