You can have it both ways. Gear Venders has an add on unit for the C-4 that's supposed to be super good. About $2000 though and a drive shaft job on top of that. These units are said to be good to 600 hp (you'd need a built C-4 to handle that). Lots of $$$, but they're supposed to be good. My $.02.
Rev
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'66 Coupe, 306, 300 HP, C-4, 13.97 e.t., 100.3 mph
1/4 mi.
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