Thanks for the reply.
By looking, It seems I would have to remove about 4.5mm just to get the oiling holes in the sleeves/bushings to line up with the gallery openings in the case. Once that is done, I think the mushroom ends will fit between the cam lobes and the spot-faced surfaces.
I will also have to factor in some clearance between the mushroom part on the lifters and the inner opening on the sleeves/bushings so when each lobe is at full lift, the lifters don't bottom out in their bores.
Many people on STF talked about the incompatibility of WebCams with anything other than WebCam lifters. I haven't heard of any premature wear issues with these lifters, and a WebCam, but I have only talked to one fellow that installed a set of these. He told me that he could not use them because of the lifters falling out of their bores. Must have been a mighty big cam he was using
So here I go...into the unknown...
Yetibone