Stuart what your are describing as having in the shop is what I mean. I checked out the auto parts stores and they range anywhere from $65 - $100 which I think is mighty steep. Basically because its got some speed equipment brand on it. Someone suggested a marine supply house should have and they do but not the metal type. They sell for about $35.
I will check the links posted above and see what the numbers are on their products and then get back.
Thanks