I was out lookin for a diff and some heads and was given a cool tip on how to ID the light duty castings. Heavy duty castings will have one cut out at the end of the head on the short head bolt side. Light duty castings have 3 cut outs, front, mid and at the end. That and they will nearly always be cracked at one or more head bolt holes. /forums/images/graemlins/angryfire.gif Just a lil something I thought might be usefull to know.