Grigg I hate to disagree with you, but you're wrong.
I drove 12 round trips from Santa Fe to Denver last year in my truck, and that was 800 miles a round trip. Every single one of those trips averaged between 65 and 70 mph.
So I think the 235 is a LOT more durable than you give it credit for. Either that or else your 235 is not very well built.
Yes, it is more durable than I give it credit for, and as such I expect it to last a long time with proper treatment.
My experience comes from driving my 52 3800 with a 55 235 that I rebuilt, Dana axle with 4.56 gears, and about 33" tires.
I drove this truck 8,000 miles in less than a month, from VA to CA to WA to NY to VA.
I also had a digital tachometer on the dash, but no working speedometer, speeds were figured by dividing the number of miles driven on the highway by the time, usually about 20 or 30 miles in a calculation.
I drove west at about 2400 rpm, and the engine was happy, and fuel consumption was not bad, speeds were about 50-55.
Driving east I was running out of time, and pushed it faster, about 26-2700, and the engine still did fine, but burned noticeably more fuel.
At one point in Canada driving from Windsor to Niagara falls on the highway I was in the right lane and being passed as if I were in reverse, so for a few hours we drove at about 3,000, still no problems.
Just for fun a few times I did have the truck over 70.
I am not saying that a 235 can't be driven fast or at reasonably high RPM, just that above 2500 rpm or so there is no point, as fuel consumption increases and engine life is shortened.
For me, if I had the choice of gear ratios, I would gear for about 2500 rpm or just faster, at highway speed, as I feel a 235 is happy at this speed.
Grigg
