probably should have also stated its split duration 277 intake 285 exhaust. degree'ed several but not an expert by any means. does the procedure change any for split duration? the only explanation i can come up with is that the valve pockets are deeper on the intake side (according to the paperwork on the pistons) and the longer exhaust duration is the culprit. is this logical or am i grasping straws? the pistons have no additional fly cutting only the ross factory reliefs