Keep us posted on your build. I'm a heavy equipment operator and bus conversion guy and really like the reliable 2cycle. To get in the right frame of mind to drive this truck first shut your hand in the door hard. Once you are good and pissed off it will run like a scaled cat. As you get to know your rig pay attention to the oil level every time that you check it. Dad had a 318 in an MCI bus that would lose about 1 gallon of oil on the 850mi trip from Evansville, IN to Orlando. He noticed that the oil level was often in the same spot when he check it. Dad made a new mark on the stick at this level. With the oil at the new mark on the stick he rarely needed to add oil. The old Detroit will always drip a little oil but should not puke it out excessively.
Note: be sure to use the correct oil. 15W40 is for 4cycle engines. In most places your 2-stroke needs straight 40wt diesel oil.
1989 FLD120 with 2000 NRC conversion