Just did a search for carb spacers, and I read through a few threads started on the subject. My combo is going to be a NA 500+ olds motor. Is testing carburetor spacers something that's better to do on an engine dyno, or at the track, or possibly both? Also, any opinions on what manufacturer makes a better carb spacer than another? I have an alum HVH 1" four hole spacer right now, but after reading through some of these threads it looks like I might want to try an open spacer underneath the four hole for my new mill.