Hi!
If you buy the .49 MVVS ...see to that you get them with 8mm carbs...not the 7mm that is standard from MVVS.The 8mm carb will give more power and still perfect throttle control.
I have during my 14 years selling MVVS engines never heard or seen one with a bad (leaking) cylinder case.
Regards!
Jan K
Swedish MVVS distributor
http://hem.passagen.se/airracing