Unfortunately in today's pitbike market it's worth about 250-350. Reason(s) why you can buy a v2 head for about 350 bucks. There are a large spread of big bores for it at an affordable price. Not only that rebuilds for the V2 are dirt cheap and replacement parts are very easy to find. Where as the Kitaco head unless you want to get into custom work your locked in at either 143 cc or 160cc. Early on when the se 4v head was introduced guys found they really didn't care for the power characteristics of the stroker setup (160cc). With the new dirt cheap bbk's from TB most guys are at 165cc+ with their roller rocker heads. Also with the Kitaco head most guys go into it thinking man I'm going to be a bad arse with this 4v head. That's until it's time to rebuild it and see the cost as well as the frustration of trying to get replacement parts. You have to remember it's a 4v head so now you have double the cost cause you have double the valves, double the valve springs etc....being it's not a real popular head your options are go back woth factory components which are expensive or custom which is just as expensive if not more. Plus to my knowledge the mobster is the only one that has replacement parts for it, or can get replacement parts for it.
By no means am I knocking the head or saying it's a bad head. I personally love 4v heads. I am just explaining why it's not going to fetch the price it should.