If the SID requires a certain climb gradient (eg it specifies 6% to 4000'), then if I am unsure, I will check my performance book for one engine out climb performance at the take off weight (against pressure altitude and temperature) to see if I can archive the gradient if I lose an engine.
This will determine my take off brief.... In the event of an engine failure after V1, I will.... follow the SID (and cancel any noise abatement) or follow an engine out procedure.
I would also commend looking at a topo chart if you'd be unable to meet the gradient, especially if you're unfamiliar or it's IMC.
Happy flying,
Sid.