So Thielke's setup says "Associated Flat 2 x 1.6" for the front pistons (and 1.7 for the rears). What does this mean ? Is this some kind of a stacked pistons configuration ? The shafts only have 2 grooves for clips.

I see Brent around the Orange County tracks from time to time, but with my very limited R/C schedule now, I doubt I'll run into him anytime soon. Reedy Race in January @ West Coast, but I'd like to know sooner than that :P