You cannot use a piston and sleeve from another engine because they will be to small. Cen parts are easy to find on e-bay and through online stores such as www.customrccars.com

www.rcplanet.com

Cen racing's fan base is increasing with the release of the GST 7.7 and the Matrix line,so more and more hobbyshops are strarting to carry CEN products. You can even order parts through CEN's website.