shifting.....

Some of those autometaed mechanical trannys will burp the engine brake, on an upshift to get the engine to slow down faster. The manufacturers must all endorse doing it

 

One of the ATHS Members antique truck videos shows Don Robertson closing the straight pipes on his 1947 International before driving through Jerome, AZ. Apparently, the little town has its own noise ordinance. Robertson uses plugs similar to the old coffee thermos plugs where twisting the handle expands the rubber part between two metal plates. Exhaust is then forced to exit through the weed burners. A plumbing supply store would have plugs the right size for straight pipes. Before entering the hills, Robertson opens the straight pipes so that "we can hear the sound of the 1950s". It is a great video with the noise echoing from the canyon walls during both upgrade upshifting and jake braking. Robertson operates the Gold King Mine Museum and Ghost Town near Jerome.

 

That's the old school taking. That's the way I was taught just a few moons ago. Treat the truck right and it will pay you back.