On a SBC I really dig the Cloyes four gear set up, quite, accurate and when running in a jet at 6K they keep things in check, small blocks seem to tear chains up with big cams and heavy spring pressures at high RPM.
I don't like PJ's four gears due to the noise.

I also don't like em on BBC's because they really aren't necissary unless you run you BBC at high R's for extended periods or racing and need the longevity.
You can buy some pretty nice double and single roller TC's these days...
If you go gear drive and want it quiet, get the "Q" series and drill a 1/64" hole in one of the front galley plugs the point near the gear mesh, keeps em cool and even quieter...


GT