Welcome; we are glad you joined us, Sleeper.
I'd be inclined to install the Zongshen engine.
Zongshen makes good engines, and someone has already installed this engine in your bike. Therefore, your job should be considerably less difficult if you choose the Zongshen engine.
Spud
__________________
Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894