I mat be wrong here, but isn't a 196 the same as a 152, but with a longer stroke??
My understanding is yes, and with a taller block to accommodate it.
Been looking for thread about stroking a 152 ...can't seem to find one anyone have any ideas or knowledge about this....
Was thinking of welding on material or last resort having a machine shop cut lobs and rod and pressing it together then drilling out oil paths...
Probably because most people have neither the time, the money nor the facilities to do it themselves, even if there were a good reason to want to.
FWIW, a friend (a retired engineer) has redesigned an antique 4-cylinder vehicle engine, adding forced lubrication, five main bearings (vs four), a stronger crank, roller bearings, better rods, and some other small internal changes I don't remember, all without changing the exterior of the block. Besides sectioning old (and pre-production) blocks to get/confirm dimensions, building the molds and cores for the initial run, etc., he ran a computer program, Finite Element Analysis, to determine where problems could occur; places where flexing can concentrate stresses in revolving crankshafts, for example. His new engine has gone into production and an early specimen has been fully machined, assembled, bench tested and then taken a car up a major peak and back in Colorado before being disassembled and fully inspected.
I'm not so sure your idea would give the same reliably good results.