How rare is a mc gurk valve cover for a 216/235 ??????????????

unkamort<SCRIPT type=text/javascript> vbmenu_register("postmenu_5247777", true); </SCRIPT>
thanks ,the su are 1 3/4 from a datsun 240 z , the manifold is part triple sidedraft webber manifold and part datsun , and a lot of modifacation and renginering theres a lot of pics on my profile of the manifold in progress


HEATHEN<SCRIPT type=text/javascript> vbmenu_register("postmenu_5247733", true); </SCRIPT>
now thats what i was trying to fugar out , if the gmc mcgurk and the chevy mc gurk were different and if the chevy one was more rare than the gmc . im just glad i got the the chevy one so i can put it on my 292 with out problems !!!!!!!!!!