[quote=B1MAXX]Not doubting any of that, but an open spacer would be quickie. I have a flow bench but I'm not sure how you would set up a manifold to pull from all 8 at the same time

Most v-8 manifolds I set up pulling out of the two intake runners that set side by side, and use duct tape to block off all the other runners. It is not perfect, but after you do all of them and document flow and velocities, it gives you a better idea of what is going on. I did a couple cast iron dual plane intakes for a pulling truck class that required the OEM manifold, no welding, just work on a milling machine and carbides, they turned out very good. both my buddies had their engines torn down by competitors, who had to post money to have it performed.