Now if you want to compare a hemi to a six pac car, I've had several of both. If you have comparable cars (same gearing, weight, trans) and comparable type motors (stock,cubic inch displacement, mildly modfiied) the 6 pack motor will get a jump on the hemi in a street race type contest ( 1/8 mile or less, stop lite to stop lite ). If you run a full quarter, as the traps approach, the hemi will begin making that top end rush they are known for, and drive right on by the 6 pac car. The hemi engines are known for top end HP, the 6 pac motors pull harder down lower in the RPM range.
Both of those engines have thier own unique sound...the 6 bbls have that cool induction roar as the outboard carbs open up, and the resultant tire smoke. The hemis just have an awesome "mechanical" sound...and when the secondaries of those carters open up, you better be ready to hold on. I always thought the hemi gets that sound from those big rocker arms and the large valve covers, sort of an echo chamber. As far as underhood appeal, well like i said in an earlier post, only thing that beats the look of a Mopar 6 bbl setup is a dual quad hemi. I sometimes just go out in the barn with a beer and just stare at the hemi....LOL.