Skip, probably the biggest reason that I use ported vacuum for most combinations is to hear the cam! Adding in a bunch of advance at idle smooths things out, but I love to hear the lope. As for actually running differences, I can set the carb/distributor up for flawless operation for the lower initial timing when a ported source is used. In many cases the owner/tuner switches to manifold vacuum to overcome carb troubles. More overlap and larger lobes always degrade idle quality and have less "pull" on the carb's idle system. Adding some timing will in most cases correct the problem. Folks end up using manifold vacuum instead of tuning the carb, but hey, whatever works!
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73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),
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