Since the beginning of March I've finally been getting good cylinder head castings for the FE Power cylinder head project, and I just got the first set back from my local shop with the valve job done, so I've been working on getting my dyno mule ready to run. I've been refining the design of my rocker arm system that is required for use with these heads, and thanks to some help from Bill Conley I've got that pretty much dialed in now. The rocker system does require some special hardware though, in particular the nuts for the head studs on the intake side. These nuts have a 1/2-20 thread on one side to screw onto the head studs, and a 3/8-16 thread on the other side. The bar that goes across the head and supports the rocker shafts bolts into these nuts with some 3/8-16 bolts.
I did this because I didn't want to rely only on bolts into the cylinder head itself to attach this bar, after seeing what happens to some other heads (specifically Blue Thunder High Risers), when a lot of valve spring pressure is used. Some of you may have seen pictures of the top of the port being ripped right off the head in that case. Attaching to the head studs is much better, so my system uses that approach. As a result I need a nut like the one shown in the pictures below:
It's pretty simple. It is just 13/16" round stock, 1.4" long with a 5/8" hex cut into the top of it, so you can tighten the nut. The underside is threaded for 1/2-20, and the top is threaded for 3/8-16. Nothing to it.
I went to ARP and asked how much it was going to cost for 20 prototypes, and a production run of 300. Take a guess, folks, I'll post the answer tomorrow. Bottom line is I may be making these myself...