I agree about the sweet-spot rpm. I run at 60-65 mph for better gas mileage (261 with 2-barrel Holley AA-1 carb used on 302/270 GMC engines).
4-speed/3-speed - why does it matter? Both are 1:1 in high gear.
Yes, I have have tubes. My Cooper dealer put them in. I'll not use tubes on the '54 I am restoring - it had primo original wheels. I have been driving with the radial/tubes for 9+ years.
