Toyota Supra Forums! Join the Supra forum! - MA70 Fastener / Bolt Specifications / Head Bolts & Studs

I checked to see if ARP updated their online library to include the fasteners for the MKIII head (which they FINALLY HAVE!!) and they've made a couple changes to the product line.

The rated spec for their head bolts is now 90ft/lbs for head bolts which is the same as the studs when installed with a LOW friction coefficient lubricant (molybdenum or better). Also of note is that while both types of fasteners formerly required ISO size tooling/sockets (which a lot of people didn't realize anyway) the studs formerly used 9/16" 12 point nuts but now use 14mm (very close in size but different nonetheless) and the bolts are 1/2" (I can't find anything about that changing)... A lot of people had a miserable time in the past trying to use 13mm sockets.... I really think the last set of bolts I installed were actually 13mm though, so ARP may have gone fully metric.

If you have an older kit which specifies the lower torque spec I recommend you stick with what the included instructions say. I would not torque OEM bolts to 90ft/lbs, but rather ARP's former recommendation of 75ft/lbs.

As I'm going to copy this to the fastener FAQ thread I'll add that the bore and thread is 12mm x 1.25.