Smokey VT903

A Turbo will usually kill the Note of the Exhaust, I think by smoothing out the Flow.
BIDSTBC

Turbo's quieten all of them down, Mack used to have Turbocharger and Silencer on some of thier old turbo ID plates, I can remember a transport inspector telling a bloke he needed to fit a muffler, and when he was shown the plate on the turbo he was actually satisfied.
If you want to make a 903 bark just put straight through mufflers or muffler on it, 1 X 4" will do it, but a 5" they really cackle. The natural motors need baffles to quieten them down. A 3070 has a strasight through muffler chocked down to about 2" in the middle.

I had a LNT Louisville with a 903T in it. It was set at 450 hp @ 2800 rpm. The full flow muffler was down beside the gearbox and then a single 5 inch stack between the cab and sleeper. It sounded like a G.T. Falcon in full flight. However, it did have a worn cam and would blow white smoke at anything under 2000 revs. And overnighting Melbourne Brisbane was hard on the ears.
Plus, it only did a bit over 4 mpg @ $1.45

Tell me, why can't you hear the whistle on a 903 turbo?

you could hear our turbos but nothing like on the 6 cylinders because the short stroke v8 doesn't make as big a bang in the cylinder then the heat has a long way to travel on a v8 to the turbo so loss of heat by the time the cylinder pulse hits the turbine they dont make big pressure like the 6s and then you have the acctual roar of the v8 which may drown out the whistle a bit to just my theory trader cheers col.

same here nev if we got 4mpg we were happy but we used to fuel everyday at home so the ole boy didnt worry that much about workin out the ecconomy long as she was goin good thats all that mattered.