I'm debating selling my car and using my '85 F-250 as my daily driver, at least for a couple months. I intend to buy a new car in February. I have a 60 mile [each way] commute that's nearly all interstate. The gas will hurt no doubt, but I'm more concerned with running the 460 at such a high RPM for extended periods.

Speed limit here is 75, and realistically you'd be doing 80-85 to keep up with the flow of traffic. On the interstate, I try to keep the truck around 70mph; any slower and even the semis are passing you, which tends to **** people off when semis are forced to hop in the passing lane and slow everyone down. With 4.10 gearing, it puts the engine right around 3100 rpm, and on my commute it will stay at that speed for a good 45 minutes.

This seems too fast for such a large torque-laden engine, but I'm no expert on the subject. I have seen a 4 cylinder or two rev that fast at highway speeds, but usually these big dogs like to turn much slower.

In a nutshell, do you think extended highway driving is bad for these engines? The truck and engine have 97k miles and after rebuilding the carb it runs like a top. Doesn't smoke, burn any noticeable oil, etc. Overall it's in good shape, I don't question its reliability at all. The only hangup is how it will handle all the high RPM highway driving. What do you guys think?

 

I think it will be fine. I know people who have done this for years without issues.

 

I think your engine will be fine but you might go nuts. Have you considered putting a set of taller tires on? Good "used" tires (if you can find 33x16.5)probably won't be too expensive and might save you enough gas to pay for the tires over the next four months. Going from the stock 29" tall tire to a 33" will drop the cruise rpm, save gas and reduce cab noise (assuming tread is not more aggressive than what you have).

 

You gotta have more faith in your Ford buddy!

These 460's last forever. Just gotta beware of leaky valve cover, front and rear mains and oil pan gaskets. They get leaky over time. Speaking from experience here.