Why is it everyone hooks the're vac advance up to the intake vaccum on sbc engines? Doesn't that make the vaccum advance pointless since its advanced all the time? Why don't you just buy a mechanical advanced distributor instead. I've always hooked mine up to the carb port that only gets more vaccum as the engine speed increases and all of my engines run fine. Its also the same way the factory did it also I've been building engines for many years now and I've always had problems with hooking the advance straight to manifold vaccum. Am I just reading what everyone is doing wrong or something? Even when I went to college that is how the books said to hook them up. just wonderin that all.
The dizzy has the springs etc for mechanical advance anyway. I never used to run any vac advance on my SBC. You can't just go back and forth from manifold to ported without fiddleing with the timing anyway, because if you had it set up for manifold vac advance, and just switched the lines, the engine wouldn't want to run, and if you had it set to accept ported vacuum, if you just switched it, it would be too far advanced, and not only run the risk of knocking, but also would race at idle. At least this is what I ran into when I've gone back and forth.
The Jalopy Journal
