[rotorwrench]

The KR models were a modification of the basic WL cylinder design just like the old Army WLA "45" bike engines had. Since they are air cooled with separate piece design, it made them easy to work with or replicate. The aluminum heads crack easily due to the heat so a person has to stock a lot of parts if they run those old engines on the track. My 1948 WL 45 solo has surface cracks in the top area of the combustion chambers but it still runs OK if you don't let it idle too long. Then again, it's definitely not a KR model. The intake ports and exhaust ports are a lot different than a Ford flathead V8 so it is harder to get a good comparison between the two designs other than they are both flatheads or valve in block types.