Good plan.

When I was driving my 235 across the country it ran well and sounded good at about 2,500 RPM all day long, and would tolerate higher but fuel mileage dropped.

I used a TinyTack stuck on the dash, they're simple, cheap, and need no external power to operate.
https://www.tinytach.com/

It might be loud... the door weatherstrip helps some with noise as will a floor mat. One muffler or another can help or hurt in cab noise. I had new exhaust put on in the middle of a big trip and though the old muffler seemed fine, the new one (looked about the same) was much quieter in the cab, a welcome improvement.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-