I boxed the frame all the way up under the cab, then removed some of it and I don't remember why. I was chasing a vibration that was cured with a 1 piece aluminum drive shaft. Chased it on 2 Centurions, fixed them both that way. I will not box this frame, it was kinda useless. I am going to do the hydroboost pretty soon, think I'll pick up a low mileage gear box since mine is leaking. You are making me want to make this a "sooner than later" change. I still need to change my lifters and put in the upgraded fuel injectors. I am fixing up a house to rent and trying to build a garage, and have a full time job and 2 kids. Time is not something I get a lot of free.