[MrE]

Steve wrote, "so I found a rebuilt DDC 6v92T Silver that was never installed from a bus company for 1500 dollars, Am I correct that I can move my Rack and aftercooler over to it to make it mechanical?"

I personally would get an ECM for the 6V92. Not familiar with the Detroit Diesel site, but for my Cummins, all I had to do was search by serial number to pull up all the factory specs for the engine, including parts build, ECM, and ECM programming.

My donor bus was rated for 280hp, could have been upped to 370hp based on engine parts, just by reprogramming the ECM. I bought the tool for reading the ECM and discovered that actual miles were substantially more than the odometer indicated. I had it rebuilt with the parts for 370 + hp. Found a motorhome for sale on the Internet that had a 450hp Cummins ISM with the engine serial number listed, and used it to purchase the parts for the rebuild and reprogram the ECM.

The donor coach had two gauges, air pressure with separate dials for front and rear axle, and a speedometer. My plan is to build a digital dash, like several users here are using SilverLeaf solutions, but they only work with Allison transmissions. I have a ZF so had to look elsewhere. I found BlueFire, works with anything with a J1939 interface, using Android, Apple, or Windows 10.
BlueFire for motorhomes This would allow you to monitor your engine electronically and get rid of your manual gauges. If you do decide to get a 6 speed Allison, you would be able to monitor it also.