[scarceller]

Do not lug these engines below 3000RPM, it increases head temps tremendous amount. It's the primary reason for failed valve guides! Increased head temps from lugging these engines especial in hot summer climates will quickly destroy valve guides. Ever wonder why some engines need new valve guides at 40K mile while others can go 200K miles with minor guide wear? This is the primary reason.

Originally Posted by Jeff Higgins

I consider anything under 3,000 rpm to be "lugging" it. Unless I'm more or less coasting down a hill, or rolling to a stop. In other words, under little or no throttle. If I'm on the throttle at all, even light throttle around town, I try not to let it drop below 3,000 rpm, although I won't get upset if I let it go down to 2,800 or so very briefly. That means I'm shifting at 4,000 rpm or so any time I'm accelerating, even at a "polite" pace around town. These motors really thrive on this treatment, living long happy lives at a little higher rpm than you might be used to, if you are coming from other types of engines. These are not American V8's - they really like spinning up, even under light throttle. Try it for awhile and see how much happier both you and your car are, being a little more "playful", even when slogging through town.