you must have the cast cover gen 6 ? they make covers competition products sell one but i have used a s.a gear 78537t-9 if useing a mark 4/5 cam with out a step nose cam in a mark 6 block ? useing a mark 4/5 chain set ? a steel gm mark 5 cover should clear and will fit the big timming oil seal pan if this is a mark 4 engine the stock gm cover? many of the stock china covers will hit at the bottom were the seal hit