DO you need the NOS pattern or you jst want a racer ? you can still buy them Ross over the counter there the same as the Aircooled IT, YZ etc till like the 1980's at least.
I just picked one up cost me $50 in Alloy. Can check the brand when im home next if that helps any. But its not hard. Also some clown sell them on Ebay all the time, N.I.B