I threw a leg out of bed at 164,000km, 308rwkw, on pulp, whether it was the gudgion that went first, I'll never know. either way if its old, or your not running e85(by the sounds of it) it will give up the ghost eventually. Start saving brass, if your heading for low 300's,its in that time frame. For the sake of 50rwkw, and no car,leave it stock and leave block intact.