This is a starter kit for flow testing LS3 cylinder heads on your flowbench. It comes with are budget Performance series valve opening kit. Works on 823,5364 casting will not work on LS2 heads. Kit includes valve opening dial indicator 5/8 hex nut threaded 7/16-20 5/8 hex nut threaded 3/8-24 5/16″ rod 4″ long (2) 5/16 swivel clamps (2) flow test springs LS2 inlet flow guide LS2 1.750″ o.d. flow pipe LS2 valve opening adapter Please e-mail with any questions.