What about the adjustable ones that used a allen wrench through the vacuum port to adjust them
That feature adjusts the tension against the vacuum device, but doesn't limit the amount of advance. I don't know if a tight setting raises the required vacuum amount enough to keep the advance from using all the available arm movement.
Actually, I found an old Accel file that shows the amount of advance is what is controlled by the screw, not the amount of vacuum needed. But there is a direct correlation, that when you start limiting the advance, it slightly changes the amount of vacuum required. Either way, I'm working on a stock 440 with a fairly lumpy cam and a stock converter. A shorter vacuum swing with slightly higher base seems to be where this engine likes it.
