I did some back of the envelope math for chain strength requirements.
Assumptions: 40 ft lbs of torque at the crankshaft.
X 12 to get inch lbs. = 480 inch lbs.
Trans ratio torque multiplication 15.68 in 1st gear. X 480 = 7,526.4 psi to the output shaft.
(I think I forgot how to calculate the force lost due to moment arm between shaft and sprocket tooth.)
But, if we (for the moment) assume zero, this means if you lock the rear wheel, rev the motor to its 40 Ft lbs of torque, pop the clutch (and it doesn't slip) you actually may exceed the design guarantee of the chain, during that brief moment before the engines stops dead. (And a stopped engine provides no torque at all.)
If a manufacturer guarantees 7400 psi tensile, that is the worst sampling you will find and most will take more than that stress during it's designed lifetime.
If you plan on abuse and wear beyond these limits, then you'd better get a different chain.
However, for practical purposes, it works fine on the 550 in stock form.
Good luck!