[rabenne]

I just bought a used stock head to rebuild, I am putting a 7 bolt head on a 6 bolt block. I head that I would have to ream the headstud holes in the head from 11 mm to 12mm to accomodate the larger 6 bolt studs (or bolts if stock). I disassbemled my head and I was checking the headstud vs. the evo headgasket and it fit through... so I was relieved.

then I went to see if the 12mm arp headstud would fit through the head holes... sure enough.. fits through... Did I imagine that you had to ream the head holes?

Yes, I did verify that the arp studs were 12 mm... i dont have a micrometer for this, but it wouldnt fit in an 11mm box end wrench, yet fit perfectly into a 12mm box end.

Please help me fast!