71 198 slant new head

So how do I get one of those bolts . I'm googling head bolt kits and rocket bolts from 75-86 heads and not seeing any sets with one different bolt in it like I need.

and can I use my rocker set I already have ? Or is it so different it's not usable and may explain my timing issues and it running like a turd . Mid June when I blew the head gasket it still ran great and sooth ( no water in oil ) I was getting exhaust pressure out of radiator . It never lost water . But it ran great on and off the trialer . And I did nothing but swap the head . I reused all old parts , lifters stayed in , push rods reused in same order , and valve train all stayed together and it all went back good obviously not that one back bolt . Any one can tell me how to buy that one bolt that be amazing .