This is the TB Performance Exhaust with a stainless can for all Z50 K0-K2 (68-71) models.  Its an updated version (as of 3/15/18) of one we previously sold and the quality has been significantly improved.   If you are running an 88cc to 117cc bore/stroker kit, this exhaust will provide the most power out of those displacement upgrades.  It will fit perfectly, look great, and improve the performance of your Z50 at a reasonable price for a quality exhaust.