One thing I did notice, in our Monte Carlo I can draft behind a big truck and the air around gets quiet, plus I have to back off the throttle to hold position.
The Corvette doesn't draft behind trucks worth a hoot, the air spilling around makes it move back and forth. It is best out in clean air or following at extremely high speed, I have run up tight to other Corvettes at double nickle speeds and she likes that.
I can easily believe that good ground effects and streamlining is worth 25% in mileage savings and more at crusing speeds, especially on a boxy type vehicle....*EB
Good thing my Dad isn't your Dad he would kick your arse for drafting a big rig. he caught me doing it one time and whipped my but,took my car away for a week,and dared me to do it again. His reasoning was if you cant see their mirrors they can't see you, and if they have to slam on the brakes someone will be scraping you off the back of a trailor. made perfect sense to me.Another thing is your comparing a vette to a monte carlo the vette sits lower so it is catching mor airflow from the bottom of the rig,whereas the monte sits higher so the upper part is catching no air at all and more goes under the car. If the monte is an 88 or older you also have the benifit of a full frame for better control,and more weight, meaning les being shoved around.
all that aerodynamic crap on the truck makes it about useless.If i bought a truck it would be for what it is designed for, hauling things.if i want fuel economy i would buy a honda,toyota,or a diesel vw.Heck GM on a whole gets better fuel milage on everything than other companies. their trucks and suv's get better economy then even toyota trucks. and their cars get near or the same as honda and toyota.
