Ian,
look up the NICE products catalogue.they list all the different studs/nuts etc including long ones.
then you can order them from Repco
just looked,if you have the 7/16 thread no listing for long,#S166 stock late valiant,probly able to order custom longer or have disc drilled to fit a different stud - 1.2" thread so look at Ford type.#NS2230 has a 15.7 knurl diameter,valiant 14.3 and shoulder length of 22.8,valiant 22.0, suits xw/y falcon v8
Tex