Since the ARP instructions call for 100 ft/lbsm I assume that is the number I used when I first installed the aluminum TFS heads over a year ago. Since I am using the same heads, and bolts, on the same block, and that the head gaskets looked fine when I removed them, I elected to go with 100 on all 20 bolts again. I also have a new set of ARP head studs, but I will save those in case a more serious engine happens sometime down the road. As for "calling ARP or TFS", I would imagine that anybody you are able to talk to on the phone will most likely be a sales person, who would just be reading the same information on the website, catalog, or instruction sheet, rather than an engineer, or anybody involved with the manufacturing process.