Fuel economy is king in truck engine design. The new fuel injection system is so sophisticated they don't make much noise.

On my 39 stude with the 617 turbo it is very quiet with a straight pipe...not caddy like but still very easy on the ears. Sometimes you get some turbo whine too. Sounds like a baby Cummins.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.