Their website is not all inclusive. They are a bit old school which in this case is good. I believe that I usually speak with Philip who I think is Patrick's son.
You might also ask at Langdon's.
Langdon's I bought my GM HEI ignition from him.
Again, you might have to call.
I don't know if ARP fasteners would have what works, but they deal with bigger volumes and aren't stovebolt specialists.
Todd
