1972 250 CR, change to WR ?

Not happy with the CR trans, just not right for my use as a trail bike. I'd like to change it over to a WR. Looking at the parts manual I'm finding that the ignition & flywheel are different. Also the crank end that attaches to the flywheel is different. Is the porting in the cylinder also different ? Compression different ? Any advice on making this conversion ? Might be easier to change out the bottom of the engine as a unit. Anyone know of a good 250 WR engine for sale ? I'd also be interested in buying a complete 250 WR if I could find a good 1972, 73 or 74.

I think I have what your looking for if you still need it. A mostly complete 1972 250WR.

Thanks for the note. I'm very interested. Please contact me at geech34@cox.net or call me at 316-706-6364. Where are you in Ks ?