In my limited dyno testing on a 500 inch motor with similar cam size (248 @ 0.050, 0.605"), the Holley SD with a small venturi 950 made considerably more peak power and more average power than the six pack. I think most folks state or claim the six pack is as good or better than the Eddy 2x4. I don't know if that is true, or how the Weiand compares to the SD.

With that, my guess is if the goal is just max power between those two, probably the Weiand/950, but that is a lot of extrapolating to come to that conclusion. I'm not sure any of this helps.

FWIW, the 440 2D and the SD were similar in power overall. The SD had a few more hp up top, but the 2D had a little more in the lower rpm resulting in about the same average power. The 2D will fit under the hood.