Eat its self? That's your opinion and your entitled to it. Obviously if the valve springs limit the rpm you won't be using that rpm would you? The valves would be bouncing. And power drops off sharply at around 3600-3800. The oiling system and engine parts are perfectly within there capabilities at this speed.In top gear it won't get near 5000rpm, so it won't eat itself.
The fact is, a Flathead is a very good, very strong very well lubricated engine. Think of the life these things had in commercial operations, screaming there heads off in low dragging God knows what up God knows how steep a grade. I've said it before and I'll say it again, they aren't made out of chocolate and cheese! They can take an incredible amount of abuse, and still go on. If they are properly rebuilt. And won't be hurt at 70 mph even with the 4.11.
These engines deserve more respect than your giving them.
Not all overdrive trans swaps need open drive or lots of fab work. Sure a Columbia is cool, but the cost of a properly rebuilt one? Easiest has to be a Mitchell, Big Brown Box and wrenches, job done.
Martin.
