Super Bronc Clutching Question

#1
How big was the original driven clutch on the super bronc? 6" or 7" ?? I just scored a Tec HM80 for $30 but needs a new carb (getting a new one) Now I have some motivation to start working on it. I can't decide if I wan't the Comet 30 or 40 series clutch's. The 40 series only have a 7" driven option.
 
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