I have repeatedly been told that in 1972, dry sumps were legal and used, but this is not clear from my reading of the rulebooks (whereas in 1971 it's very obvious that it's legal). I must be missing something, but you can't hide it. Could someone point to where it says dry sumps are legal in 1972, or what the loophole is? There is obviously a small opportunity on page 124, #17, but is that the exception. TIA. Also - thank you Jon for memorializing the rules. This is very helpful to me and I am sure to other enthusiasts as well.