Who offers cylinder sleeving for the DT-1 family engines?  Specifically for a 72 DT2MX.  I see Vintco and LA sleeve but not for the older DT1 family. 
As another option, how well does the DT2/3 cylinder work with a DT2MX lower end?  Any guide lines to port a DT2 cylinder up to near DT2MX performance? US based please.  Thanks

Personaly I'd be looking to use an aftermarket piston kit from a yz or something with the same pin height even just a dt2-3 kit before looking at sleeving. Had the best days of racing on my dt2mx when new but was only on first over when I sold it. Went to an mx250 next which in my recollection was a step sideways rather than up. But worked for the agent so had to have the flavour of the day haha.