There's nothing wrong with Speed Pro pistons, but I "think" the KB's are lighter too....engine revs up faster, less bearing wear, higher rpm potential.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
