#64 means its a 250A case, dont mater whats inside, but on the outside you have points, meaning either they are the early 72/73 mx or for some reasont your ignition shat itself and rather than repairing the bit that went poof probally the coils or the Cdi they just found the Dt or whatever it is from an enduro cheaper and fitted it on, what are the number on the backing plate or flywheel ? there will be some numbers on it somehwere. what does the box the wire go to say ? it wont have a CDi box but somthing else where the wires go to will have numbers on it , or better still take a good foto of that, and a front-on foto of your stator/flywheel set up, post it back in here and with in 20 minutes you will have a correct answer. Now Over to you and theBrains trust