The 4-53 would be a 1900 or a 1950. The 1950T is a little Waukashau turbo.

I have a 1950 just waiting for the owner to decide to sell it.

The oilfield service outfit we drag around a couple of fields here quite a bit has a frac truck with a LARGE Detroit on it.  I'm not sure what it is....it has 16 holes and it's not a 71 or 92 series.  Turbos all around and then straight pipes.  When they start to crank the pressure up, you want  to either be in the Challenger cab a ways away or have your ear plugs in.    At idle it's about as quiet as a car engine, like all Detroits.  

Local independant spray outfit has a gaggle of Big Wheels Gimmy's with Detroits in them.   Allisons of course.  They run the road south of our shop a lot, with a highway crossing right next to us.  I always wondered about the operators because of the sound of them coming up to the stop sign with nothing but tire whooop whooop whooop, then  all the sudden the Screamin'Demon springs to life and they go about a half mile at  2100 RPM as the torque converter gets the rig back up to the speed of the engine through four gears.  Since I've got some experience in an ALlison with our Silverwheels I realize that the only way you can drive the automatics is WFO so that they will shift correctly. 

Detroit Diesel plus Allison......and a 12V with turbos at that.....I don't know how you could get any better.    I want your truck!!