cooling wise, there isnt much difference between them.
usually the hose fittings are differet but with a bit of determination, yes...
125 is head fed, 140/150s are fed straight from the pump... usually.
youll need new hoses. lengths are definitely different.
could always jump the outlets from the pump on the 150 and use the plate on the head that the 125 uses... should just bolt straight on, 3 bolts. then hoses will be no probs. and means you only have to find a jumper hose...take a peek at the "tearing down the head" tute...thats a head feed that dabomb has pictured....with banjo bolt fittings. some use just plain hose clamps