On the distributor collar issue...if the gear moving up and down won't affect timing, then why does the timing get much steadier after installing the collar? Is something else going on here? I've done this on both of my own engines and the timing most definitely does not move around nearly much w/ the collar on the distributor from my experience.
Does it "really" get steadier or does it just seem that way 'cause you've just spend an hour messing with the distributor?
Honestly can't answer your question but the facts speak for themselves, the way those gears are cut there's no way that drive gear should rise up under any sort of load. If the cam moves fore or aft then, yes, timing will vary. But not because the drive is moving up or down but because its being rotated slightly from the cam movement.
Those collars were first implemented and marketed (to the best of my knowledge) by Ed Hamburger. Ed was a smallblock guy and I think a lot of guys jumped on those collars thinking they'd help on big blocks. Unless I'm mistaken, on a smallblock the cam rotation WILL drive the oil pump drive upwards and affect timing, hence the collar.
