new master cylinder or rebuild?

Great info fast and thankyou! I plan on buying the Dak master,but my parts guy is playing with research in his spare time in hopes we can find another option that may bolt on without an adaptor. Until then I will suck the weight penalty of the original cast iron master. At least I KNOW if I rebuild it I have the correct unit and it'd been built right.

Yea I know china crap is here to stay.

I do have the original p valve for disc drum but I might just get the adjustable one. Rear tire lockup aint funny!