MaximRecoil

"Twin V6's"? How would that work exactly? BTW, the number of cylinders has nothing to do with how much power a motor can make. You could make a 1,000 horsepower 2 stroke 1 cylinder if you wanted to though it would rumble so violently that it would tear away from any motor mounts instantly. In general, more cylinders = a smoother running engine. Displacement is the major factor along with being able to circulate enough air through the system. More cylinders usually = more displacement but this is due to practicality, not necessity. A 500 cubic inch 1, 2, 3, 4, 5, 6, 8, 10, 12 or 16 cylinder could all be built if anyone wanted to and they would all have similar power potential.
The most powerful internal combustion motors for cars on the planet are hopped up V8's, Hemi's usually. They are in top fuel dragsters and make over 3,000 horse and can do the 1/4 mile in about 4 seconds at over 300 MPH.
As far as Cooter's truck keeping up with the General Lee; it seems to me that most everything kept up with the General Lee. I can't think of any scenes offhand where they simply floored the General and left anyone in the dust. Those emissions-era bogged down 360's in the Chrysler B-body cop cars, the random 4 door sedan "Bad Guy's Car", Jesse's 300-6 powered Ford F100's, Daisy's 304 AMC (at best) Jeep, Cooter's various "tonners". Boss Hogg's 472(?) Cadillac -- all seemed to be able to keep up with the General Lee. I would say that it was because it is hard to make an interesting chase scene if the General just leaves everyone in the dust.
About Daisy's car (the 1971's in particular); that was the same car as the General Lee for all intents and purposes. The 2nd generation Chargers and the 2nd Generation Road Runners didn't share any outer body panels but they had the same chassis (B-Body) and pretty much the same drivetrain options. They both could be had with a 426 Hemi; the '71 Runner could be had with a 440 6bbl and the '69 Charger could be had with a slightly less powerful 440 4bbl. The 383 was available in both of them but only a 2 bbl version for the '69 Charger and a higher performance 4 bbl version for the '71 Road Runner. Transmission and rearend options were the same on both cars.
In 1972 we hit the start of the emissions-era (and no more Hemi) and by '74 it was in full swing. So while identical drivetrains could have been optioned on the '69 Charger and the '71 Road Runner; by '74 (like Daisy's original car was; from the first few episodes); all Mopars; even, all muscle cars, were mere shadows of their former selves. No "muscle car" from '74 could touch a '69 Charger R/T.