This is a forged +3mm stroker crank with +5mm connecting rod for RC engines. The journals are larger in diameter for added strength and balance, plus taking up more volume in the crankcase for a 'stuffing' effect. This will require the use of a base spacer and/or a head kit. Using this with a 36mm bore will make a 31.6cc monster! Please note that this is NOT a bolt in mod. Using this requires proper cylinder spacing to obtain the correct piston to head clearance. This is for experienced engine builders only!