R35LEE at Falcon Performance is probably your closest Z specific mech. Probably worth paying for the hire of a trailor to get it to him, he will be able to point you in the right direction for that.
Hate to say it, but if something serious has gone, its likely to have been oil starvation from the previous owner. Its quite a common problem I'm lead to beleive, lots of owners manage to let the oil get low which the Zed really doesnt like