It's an option you don't seem at all interested in. But my car runs pretty good on manifold vacuum. I've got a SCV 1100 carb on it with the distributor vacuum port plugged. The distributor is a stock 1970 single vacuum can version that I think might have actually been for a 250, and it is connected to manifold vacuum. Well, it's actually an extra vacuum port on my carb spacer that I made, so technically it's not on the manifold. Any way, it runs pretty good. Idles well and runs strong (well, for a six...) without any pinging that I can hear with timing set at 12*. Hit the gas and it takes right off, no hesitation or stumbling as revs build. My long time 1100 had given up the ghost, so the carb on it is a chimera I put together using parts from a couple different 1100s I bought on ebay because most of the ones on there are pretty well used up. I spent maybe $125 on them and a carb kit. The distributor cost me about $75 as I recall. I'm not using the manifold vacuum because it's an existential philosophical choice that I've made, but because it's the easiest and cheapest thing to do with these parts. I'm hoping to find the gumption to finally get my E0 head and a non-SCV 1101 carb on it later this summer. And with that combination I'm planning on using the ported vacuum tap on the carb.