Originally Posted by jon@work
some people no longer recomend the use of the short ARP studs - stick with the standard headbolts, or fit the long studs from Mountune.
"31" are the last 2 digits of the part number of the "-31" actuators
bollox....i have ARP bolts fitted...works very good..no problems what so ever..
and some scandinavian tuners use them also....