Yet another comparison (air-gap carb spacers)
Tested two spacers Friday night at the track. The split spacer didn't even make it that far, I could tell from driving around town the engine was not happy with it. So, I made two passes with each spacer (open wood and HVH super sucker tapered 4-hole, both 1"). Best pass with the open wood was 7.89, best pass with the HVH was 7.86 about a half mph faster. This is on an 1/8 mile track, with a 6800' corrected altitude (5335 uncorrected) within 15 minutes with those two runs. I also massaged the center divider so fuel wouldn't puddle on the flat factory casting, and the outer edges were matched to the spacers. Thought I'd have to mess with jetting, but the plugs all looked the same between the two spacers. I also ran out of time because I entered the mixed class gambler race. Wound up winning and being $500 richer, so that paid for the weekend, parts and then some.
The car is also a solid tenth faster in the 1/8 than the super victor manifold. Not sure how much carries over to the 1/4, but I'd say at least that judging by the mph.