Keep in mind that the 67 didn't have duals - well for the small block engine anyway. You'll notice that the gas tank is more to the right of center than on later models. I'm not sure that Accurate's 68 and above system takes that into consideration. I had a custom install on my 67 to
create a dual exhaust system and the guy spent more time bending the pipe that goes over the rear axle on the right side than practically the whole rest of the system combined. There's not much room there. It's possible that's where some of the $800 - $900 cost is coming from.