Smilinjay
Proven Member
- 290
- 97
- Jul 9, 2013
-
Anchorage,
Alaska
Hi everyone, so i am going through my 1g 7 bolt head and i have a question about the head stud hole diameter. I took this head off of a 6 bolt block that had been run for quite some time to put on my block (my stock head had bent valves)c, and ran it on my stock block for about 800 miles. Since then, my motor has suffered main bearing failure. Anyway, i am trying to verify if my head bolt holes have been drilled out for 6 bolt arp head studs or not. I read somewhere that a 1/2" drill bit should pass through the head bolt holes on a 6 bolt head. Using this logic, i assume the same should be true if the 7 bolt holes have been drilled out to 13mm. A 1/2" drill bit would NOT fit through all of the holes except the one closest to the firewall on the timing belt side. This baffles me as the head was pulled off of a running and relatively healthy block. If it matters, my arp studs pass through the holes with quite a bit of play. If anyone could verify what i have described, that would be a huge help.