Mr Fast came through (
), here is what he said;
"Talked to Owen and as I suspected he had to auger out the opening where you insert the cam into the rocker box to get the high lift cam to fit. Interestingly, after inserting the cam he had to grind down a ridge in the rocker box
so the cam could spin! Make sure yours will turn over after you get it fitted."
After receiving the information from Mr Fast, I did some further research on the inter-web and came up with this build thread, from another CB350 roadracer;
And his quote (from the engine portion of his commentary);
"You will need to clean out the entrance for the cam in the cam box so the redesigned cam lobes will fit. You will also need to clean the ridges off the cam box floor and enlarge the opening in the cam sprocket. That's all you need to do fit the new cam."
So time to get out the grinder and make a little more room!