The difference in measurements between 1740 and 1182 are huge, and even with the cedar added to 1182's case its still 60mm further forward than 1740's..... measured from the front beam to the front of the board case.

At D.Y.C. today and I had a look at Al's boat 'Scorpion' and he has a block aswell only his has been placed at the back of the slot pushing the boards as far forwards as possible, his slots are even longer than 1182's.... I ended up with just under ~40mm long cedar packer and Al's would have to be nearer to 55mm of packer.

I'd have to agree that the boards themselves are not designed to run with the setup on the boat although the style and length is from that era as I remember it (recall seeing the dual timber boards and thinking how good they looked when I was moving from jnr-snr sailor), as to what happened with 1182's is anyone's guess....
My first mozzie STINGA #245 had a wide long board and the rudders were narrow and long comparison, much like 1182's are. I remember making a new set of blades that were shorter and wider and could be pushed far further forward under the boat than the old ones to get a better turning boat on the tacks, I also remember cutting off a couple of inches from the width and the length was also cut down on those boards once the rudder mods had been proven to work.

the rudders that came with 1182 are the same in their shape and style in that they are also long and not that wide. but as to what / where / & when the changes were made..... ??????????????????????????????