Whats the most rpms do you want to run at 70 mph without hurting the engine?

 

Anything under redline? I dunno for extended highway cruises I don't like having the engine over 3000 (my truck is bad about this [:'(]) but that's more of a comfort thing and I doubt it hurts anything.

 

Yea technically stay under redline and your engine won't blow up, but what's your point of maxing RPM's?

The higher you constantlyrev your engine the faster it will wear down, the more noise it makes, the more fuel it gulps, the faster the accessory devices (alternator, a/c, etc) will spin & wear out.. it's all bad [:@]

I've seen kids cruising down the street in like 1st gear just so their engine is screaming,, I guess they think that's cool? [&:]