It's hard to beat the torque of stock zilla engine much less one that has been properly modified for optimized torque. Just so you know, the 87 jug along with all associated components will fit on any later case & vise versa. Your builder of choice knows a thing or two about these engines & is known world wide for his work. It sounds like what you might want is his dune ported build. If you go this route, you might as well also pick up one of his pipes as well. You won't be disappointed.