


Again, this is a '75 case with the wall at the correct height.





Screenshot below via Ozebrook site....showing a plastic dam. Reproduction dam available from Clauss Studios


If the engine is still in the bike, might be able to just reach in with your camera phone, flash on, just so and catch enough of the wall to satisfy you the mod has been done or not or just use a good light source and small hand mirror as mentioned before.
Another way of telling would be just to set the end of a narrow ruler on the wall and measure the distance from the top of the existing wall to the top of the vent hole. I'll get a pic of that measurement for comparison on my '75 case next chance I get.