Upper ARP head studs don't thread?
 

I'll try to explain this, hopefully the pics make more sense.

The top five ARP support studs for clamping down the heads, well, don't clamp the heads down.

They're threaded on both ends. The coarse threads for the block, the fine threads for the nuts that hold the head down. Now, the coarse end is installed hand-tight per the directions, then the head goes on along with the moly-lubed washer and nut combo. Supposed to torque down to 22 ft lbs, and done.

Well, the threads are only cut on the stud a partial length of the way down. The ten main 15mm nuts have been torqued properly, and these upper support ones last. However, the nut only goes down to where the threads end on the stud, and this leaves about a 1/4" gap between the nut and the head surface. In other words, no clamping support from the upper support studs.

See the pics for what I mean. So WTF is this all about? The PN# of the studs are ARP 234-4110, LS1 six-point head studs. I've searched and seen these used on all year blocks and heads, so anyone have any idea what gives?

It seems ARP may have packaged these wrong?

http://www.unleadedanalog.net/pics/stud1.gif
http://www.unleadedanalog.net/pics/stud2.gif

Oh yeah, all five do this and are the same length. This isn't just an isolated one with the possibility that it's "stuck" because the threads in the block weren't cleaned.

Me thinks you ended up with the wrong studs. :cry: