You mean bolt spacing and that is a thorn in my side. There was absolutely no reason to move those bolt hole locations. The runners do not encroach whatsoever. Imagine being able to bolt a Weiand 7576 X-celerator to your W2 heads-wow. Talk about ultimate smallblock. Then again , that train left the station as soon as the G3 hit the scene. Onwards and upwards. J.Rob