Since I hate torquing steel bolts into aluminum, especially if I have to do it several times, I want to use main and head studs instead of the stock main and head bolts that come with the LS7. I have the ARP 234-4317 SBC LS1 Pro series 12 pt HSK which is supposed to fit the LS7 too. The LS7 block has 19 threads in each of the 20 head fastener holes but the ARP head studs have only 14 threads on them. I don't want to give up 5 threads of strength in using the ARP studs. Does anyone know of a head stud kit with studs that have the full 18 or 19 threads on them?

 

After a little messing around and several conversations with ARP I decided the easy way around my dilemma was to buy a high-speed steel, 11mm x 2.0, thread cutting die, cut four or five more threads on the ARP studs and shorten the guide bosses on the block end of the studs by about 8mm. By doing this I pick up about four more threads (8mm) of block grip and I have 8mm less sticking out of the nuts which hold the head on. Unless these newly cut, rather than roll formed, threads create a significantly weaker fastener I will, in my opinion, have improved the piece. ARP is having me fax them all of the specs on the block, heads and main caps. I hope they will tool up to make LS7 specific studs. W2W's Curt Urban counted seventeen threads on a C5R head stud he had in his shop and the stock head bolt I screwed into an LS7 block engaged seventeen threads for what it's worth. Why all the bother? Just for the hell of it!

 

Jeff K. at ARP says the LS1 head stud kit fits the LS1/2/6/7 correctly and that they have no plans to change it. He didn't recommend cutting any more threads on one of their studs as their threads are rolled rather than cut because rolled threads are stronger. Since my seat of the pants engineering tells me those studs are plenty strong even if I do cut some extra threads I may do it anyway. I have an adjustable die which I can open up so I don't damage the rolled threads and I can set to cut shallow threads.

 

You may damage the heat-treat ARP uses. I'd ask their tech guy about that.
If you're remaining N/A I would not alter these fasteners.