I have been using the Holley 70mm set for 2 years and they are by far and wide the nicest throttle body I have seen, and I've seen them all. The part is fully CNC machined from a solid piece of aluminum, not cast like all of the others. There is no binding or vacuum leak issues. The only, only problem with them is that you must use nuts that do not have intergral washers like the factory nuts because Holley did not leave enough room for the washer to seat properly. I replaced them with nice SS nyloc nuts. Also, the right bottom nut must be turned just right so the throttle stop does not hit it and limit the throttle blade movement. I would never use any other brand.