found another good pict of a flawed gear
sorry linky is gone from the post mentioned below, putting another one
in
theamcforum.com/forum/the-cam-distribut ... page4.html
Also a good note from SC397
The gears are not Hypoid type gears so, the depth of the distributor gear meshed with the cam gear is not that critical with. If it was that critical, there wouldn't be .050" end play in most of the OE distributors. Of coarse, you want it to be centered as much as possible. What is critical is the engagement with the oil pump shaft. You don't want the distributor shaft clamped down so tight to the oil pump shaft that there is a load on it.
The distributor gasket helps shim the distributor to the oil pump shaft as well as sealing it up.
As mentioned before the issue with the early aftermarket covers is with the bottom driver's side locating dowel hole. They were off causing the whole timing cover to be shifted the wrong direction causing a bind when you stabbed the dizzy in.