amsoil recomend 20/50 in all holes what do you use in your 1558 softails

Mobil 1 15W-50 in the engine- just as good but easier to find (at any Wal Mart) & half the price.

Gearbox- any good gear oil like Mobil, Rotella, Redline Shockproof, etc.

Primary- after trying a half-dozen different oils/lubes, I've found Formula+ works best.

20w50 in the engine. It will work in the primary as well but get a 75w90 GL5 gear oil for the trans. Amsoil makes a 75w90 & 75w110 severe gear that will work better and last longer than the 20w50.

what about amsoil 80w-90 gearlube in the tranny? Is it any good?

In both mine
Engine M1 Vtwin 20/50
tranmission six speed Spectro Platium GL5
five speed Redline shock proof heavy
Primary F+