Well I think I finally came up with a plan as for what sled I'll ride this winter. Lately I've been debating between an IQR or a ProX (if ProX preferably an 04 XR). I just had a guy offer me an 04 Pro XR440 complete nice sled for a great deal, so if I get this then I would pull out the 440 and drop in a 600VES. But here is where I need some help, what if I didn't drop in a 600 but a 500 instead? The reason being is I have two nice 500 VES engines and no 600 VES right now. What ever I do I want it to look stock. So if I use a 500 VES, can I use the 440 exhaust? Also I want to use the stock air box, so what carbs do I use? I will use the 500 CDI and wiring harness and I'll also have to look for a place to install an oil tank.