What no one has addressed here is that a lot of the new roller chains have 3 different keys on the crank sprocket. They come with Sq. key notch, an triangler notch, and a circular notch. It depends on which notch you have installed the gear on the crank shaft. That is the notch that must line up with the top gear, otherwise you could be off a ton on the timming of the cam. Basically when everything is right the harmonic balancer should be at 2:00 on "0" with top dead ctr. of the engine/number 1 piston.
Zip.