Car and Driver mag had a muscle car shootout back in '66 that they ran at Bridghampton and at a local strip...Comet also won 1st overall against the 396 Chevelle, GTO, 442,Fairlane GT and Buick Gran Sport.... and this car also had the Bud Moore treatment and was quite a bit faster than the Fairlane GT...."and smoked a lot" said Brock Yates....
I don't have the mag article anymore but I'm sure it on the web somewhere. I would almost bet on it that the '66 Comet used the C6AE-R heads and intake and was tuned up a bit with a warmer cam........as I recall, Mercury also sent a small group of Bud Moore mechanics to keep it running right during the off track down time.
I'll bet that 375 fwhp with headers with a cheater cam is a good number for those Comet Drag cars...
With the factory exhausts probably 340hp in the Car and Driver test..quite a bit better than the stock GT numbers of around 300 fwhp. No way those were rwhp figures..
I read every article I could back then when i was in college and caused me to lust after the cars..... and I got a '68 Torino GT 4 speed car in '69. Traded in my '62 Plymouth Fury convertible on it...