aaronc7

iTrader: (8)

I understand the 218-4701 is the ARP part number for head studs for the BP motor, and that they are 7/16" diameter, but I am having a hard time finding much more info on them beyond that (what thread pitch, for example).

http://arpinstructions.com/instructions/218-4701.pdf

Reason I am asking, I need to get just the washers and nuts.... have the studs already from the above mentioned kit. Does anyone know which nuts and washers come with the kit? I screencapped the available options from their catalog below.

I know the nuts are 12-point and I'm pretty sure it's the -20 pitch thread, based on just looking at them. But then the different flange sizes/socket sizes, I have no idea and have had no luck searching the web.

They are closed for the weekend, figured I would ask here in the meantime.

midpack

iTrader: (3)

If you still have the stock washers they and should can be re-used instead of the ARP ones. Stock are slightly larger diameter than ARP. The nuts are 7/16" x 20.

Don't follow ARP's instructions and over-torque (80ftlbs) them or you risk damaging the head. Here's a good thread to start with on ARP head torque. I used 60ftlbs, IIRC.
https://www.miataturbo.net/engine-pe...e-miata-54746/

aaronc7

iTrader: (8)

Thanks. Turns out I am missing a few other things, so I am going to have to run back my builder's shop anyways. He should have my original ARP nuts and washers.

I just read through that thread again today, a lot of interesting info in there.