I agree that the lower highway speeds are more comfortable. Even though I could go 70+, the engine ran awfully hard to do it, but it held up. I usually cruised at 65, and although I got passed a lot, it did teach me the rare virtue of patience.
I've gotta tell you though, there were two modifications which helped me obtain that last 500 rpm, as well as enough torque and power to exceed 65 mph at will. That was a 2 barrel Holley/Webber carb from Langdons, and a Pertronix electronic ignition conversion from Summit. Before that, any mild grade uphill and exceeding 60 was a challenge.
If you think about it, the Blue Flame 235 in the Corvette made its peak horsepower at 4200 rpm. I know it had its own cam and some mods, but the thing to observe was that the rotating assembly was tough enough to take those kinds of rpms. I think the bread and butter 235 feels like it's running so hard at 3500+ rpm mainly because of the extremely mild cam, the choking 1 barrel carb, and possibly the points. Naturally, a set of split exhaust headers would improve things a lot too, but it appears Fenton for some reason decided not to make those anymore.
However, I've seen tubular split exhaust 235 headers at Speedway Motors.
