well u have about 4 options. first buy someone elses headache off of ebay and not know what u are getting into. second, by a engine from yamaha and get ripped beyond beleif. third get your rebuilt by someone reputable. and last rebuild it yourself and save some money and actually know that its a good build. it will also give you a little pride when the new build runs like a scalded ape. i will build it for you if you arent up to the task. but remember speed cost money, how fast do u want to go? i will split the case and rebuild with what ever you want for 200 bucks. u supply the parts.