revive! 
noticed the 40/45/49 share most of the parts for the 2040/2045/2050. is there anything that can be done to them like the husky 345/jonny 2145 being able to convert them over to a 346 top end?
You'd have to make a 350/2150 style riser block (to bolt the cylinder to) in order for it to work.
Yes, and the stroke is 32mm vs. 32.5 on the 346xp, 350 etc.