Nortons spent the cash and had a number of full blown race bikes designed over the years - mostly fours - and then didn't proceed with them,
for various reasons. Also that laydown unit construction manx in the early 1950s, and again didn't proceed.
The (traditional) manx diverged from the road bikes by the mid 1930s, and then had a life of another 25 years,
so its difficult to claim that is shared ANYTHING with the road bikes whatsoever, for a large part of its lifespan.
But as we have noted here before, H*ndas canteen probably operates with a (considerably) larger budget than Nortons race shop did per year,
so 'shoestring' operation, or 2 men in a van phrases come to mind. Bearing that in mind, the success of this operation was considerable.....
But yes, designing for race or designing for road are 2 quite almost opposite aims, and never the twain shall meet. ?