Originally Posted by Augusto
how much total advance can this engine run? or should run for best performance? and at how many rpm?
the distrubuitor I'm using is a Motorcraft points type (late sixties maybe) with dual pot vaccum advance, I have only the end fitting of the vaccum pot connected to ported vaccum, the other, the one closer to the distruibuitor body is left open to the atmosphere. There's nothing in the vaccum line, like restrictors delayers or something, just a straight hose from the carb to the pot.
it's not a race engine, it's a daily driver but having it performing well is really cool.
I'm not that familiar w/using the Ford 300 in a performance application- not that there's anything at all w/doing so, so I'm at a loss for "hard numbers" for timing.
I'd set it up to give as good of vacuum at idle as the initial timing will allow, then bring in the mechanical as quickly and as much as the engine/fuel/vehicle combo will allow w/o detonation. Basically same as any engine would be tuned, w/o having any predetermined numbers to work from.
But I just feel certain that you can work out a curve that will allow more initial- and that's the key to getting more vacuum and better throttle response off idle.
Be sure the vacuum chamber that's being used is advancing the ignition. You might try dialing in the timing w/o the vacuum advance at first, then bring it online after the curve is dialed in.