I was talking about the Jerry Branch short rod KR, photo and titbits of info on page 116 in American Racer 2...
Waffle Iron XR had std KR/XLR rods in 70, so were just short stroke. The factory Iron XR got to prototype the shorter rod from the alloy XR in 71 so they were both short stroke and short rod. OB has stated that they got about 80BHP out of these later Iron XRs with the reworked twin carb heads while the proto alloy XR was worth about 70BHP in 71, But he obviously knew development would soon cancel the difference!!!
panic: the existing race cams are all too hot
Yes, but in the case of the XLR/Iron XR, it's all about getting a big overlap to compensate for the high dome that masks most of the overlap period by sticking so high... Same for std Sportsters actually...
panic: meaning the heads need a major re-design with smaller ports and valves
See previous photo, these are Iron XR heads, fitted with smaller cores before pouring. You can see the outline of the std core as well!!!