JVAB and RSI ARP headstud confusion

[Lucky the Smiling Pirate]

So way back when, JohnV offered a head stud kit for 8v and 16v people. The only difference between the two was that he provided some spacers for the "short studs" on the 16v head so that all 10 would use the same studs.

I'm in need of a replacement nut from ARP but I have no idea what part number to use. I'm having a heck of a time finding documentation from JohnV because lets face it, he's horrible about **** like that, and he may be out of the country right now.

RSI can't confirm or deny that their kit is any different than Johns, except to tell me over the phone that they specifically use two DIFFERENT nuts for the 16v kit.

If anyone knows what part number I need to tell ARP I want to order, I'd really appreciate it.

 

[Lord_Athlon]

Can you measure one of the other nuts?

 

[Lucky the Smiling Pirate]

caliper batteries are dead, don't have any thread gauges.

 

[fidel]

for 12mm studs both 8v and 16v (assuming they are the same ones we sell)

the nut is AUN12.2 (its 12 point)

the washer the same size as oem bolt heads AUW875n

 

[Lucky the Smiling Pirate]

okay so the nut is a 12point m12 x 1.25.

this is either an 300-8307 or -8308 with the 308 being "small collar"

how do I know if I have a "small collar" nut?