Apparently while talking piston UTG brought up in passing that he read Smokey use too knurl pistons and Smokey said he gained hp, now people are debating if it would, Brain said he gained like 8 hp but lasted only one 250 lap race.
this has been hotly debated in the 2T world for years...
the "theory" runs that old song of a loose motor is a fast motor, but when piston to wall clearance gets too big they get noisy at best, and toward the other end start wearing the bore from slamming into it or just breaking off piston skirts. so the tinfoil ball cappers think: if i knurl the piston, it'll hold more oil and that'll cushion the piston and provide more lubricity to the interface of the skirt/wall while also sealing the bore.
i'm sure somebody thought of this while taking a break from their perpetual motion machine project.
could it be worth a few ponies? yes, absolutely. under the right circumstances. but with the trade off in longevity.
remember, smokey was the ultimate master of subterfuge. sometimes he'd do **** just to throw people off his trail of what he was *actually* doing. i wouldn't put it past him that he would let that "speed secret" out knowing that the motor would make more power but eat itself up in short order, which would be just about perfect in a 300 lap race. cuz ya can't win a race if you can't finish that race.