There should be kits available for that carb. Haven't seen a Walbro on an airplane engine yet that didn't have the major parts available for it. If not, as suggested the SDC-80 is pretty much the carb of choice for that engine.

That engine is bolted to a Byron Purr power muffler / mount. If it is in good shape, I would be interested in buying it at a reasonable price. I agree .... great old engine. Powerful and they'll run forever.