Well the project continues. My 39 M has the hole in the hood for the small fuel tank but there is no evidence it ever had one. Obviously a lot of things have probably been changed in the past 73 years but I have no way of knowing if it actually ever had one. Help me out here guys. Did all of the 39 M's have the dual fuel setup or was it an option? If an option did the tractors without this option still have a hole for the tank in the hood? I'm not going to switch manifolds back but would consider rounding up a tank and installing it to fill the space if it was a standard feature. Thanks.