i'm sure this has been posted before, but i've had no luck finding any answers. my car is a '78 nonturbo 300D. i finally got a new exhaust (resonator bypass, new muffler, and a nice dual chrome tip ) and inspection, so i plan on taking it up to the mountains on christmas to see family. it's about a 3 hour drive, alot highway. i've done 70 before in this car but it's LOUD from revving so high. am i causing any damage to the motor driving extended amounts of time at a speed like this? or is it just simply loud? thanks!