2 kwik

good call

67mustang302

Are any valve springs broken/damaged? If it happened suddenly after driving it for a whileit wasn't an incorrect assembly. If clearances weren't right it woulda broke the instant you started it up. Did you replace the springs with the correct ones? I'm assuming they came in the kit. Did you check them for coil bind? Are you getting oiling to the valve train? Was your rocker arm geometry correct? What are your valve guide clearances? What oil do you run? What rocker arms?