Another vote for marine engine. When boats have dual engine one turns backwards from the other. Its really the only possible thing I can think this would be.
I'll second that. A cam and intermediate gear change should remedy it, if that's the case. The only other issue might be if the crank journal rear main seal surface is knurled ////// vs \\\\\\. A reverse rotation marine crank can cause a rear main leak in a std rotation engine.
