If the engine has M8 stud s like many or most do you will need to drill the heads M6 holes out for the engines larger 8mm studs, I have a Puch Hi Hi 50cc head on a 66cc and it works fine, the 66cc is a 47mm bore and so I had to use two head gaskets to prevent piston from hitting the head since the combustion chamber on the Puch 50cc head is so small, but there a chance you wouldn't have to worry about that.
Only concern I have is if the bolt pattern on the grube 49cc engine is big enough for the Puch heads, I dont have any 49cc engines and I've never owned a grube engine of any size but I do have an older 66cc engine that has 6mm studs and a smaller bolt pattern than all my other 66cc engines and the Puch headswont work on it because of the bolt pattern being different.
Im sure some of the other guys or gals can ring in here and let you know if the bolt pattern on the . 49cc grube will allow you to use the Puch head.
Im just not sure if it will work on that engine or not.
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