Scott, where is this mark? I spent 3 hours last night, researching head bolts, and as usual, the internet has ruined everything logical. I finally rolled the dice on an entire set of ARP head bolts, but aside from the $100 tag, I'm not sure that they'll fit and I'm not crazy about mixing and matchingHello
those look to be correct 67 68 ac head bolts ,,,, seen em with and without the stud on top .. 67 n early on the 68's mostly with the stud
just had 2 later a march and april 68 ac cars and they were studless..
if you need a pair of originals non ac head bolts I can mail you a pair ,,, for deleting the bracket ...
what is the foundry mark on the top of your smooth heads... is it a sunburst pattern or a bullseye ??
Thanks Bear. I don't mind spending $100 on two bolts, but I want the job to go smooth.ARP makes several different bolt sets for Pontiac heads. They vary based on which heads they're for, and the differences are in bolt length. Round port factory heads, like Ram Aiv IV, 455SD, etc. require the bolt that goes between the center exhaust ports to be slightly longer because those heads are thicker there than the iron D-port heads. Different aftermarket aluminum heads also need different length bolts in various locations for similar reasons. However as far as I can remember without looking it up, all factory D-port heads use the same ARP bolt set. All their stuff is good though. Use the torque specs ARP specifies, not the factory ones, and DO use ARP's Ultra-Torque installation lube.