Q: Ford Solenoid Switch in Lieu of Mopar Starter Relay?

I've torn apart a few ORIGINALS, not modern chineseoeanated replacements. those are actually a fairly heavy relay. Based on what I've see, I would estimate the contacts (depending on the coil) are good for 40A or better.

And THAT is an important point. Relay contacts ratings depend on the shape, pressure they are under, and the material they are made from. This is why STARTER solenoids (Ford) are different from "CONTINUOUS DUTY" solenoids. The contacts are not "rated" at as much current mostly because the coils of the two generate very different pulls. The Ferd relay has MUCH more magnetism, but the coil cannot be left energized for long. The continuous relay has LESS magnetic pull, but the coil is (allegedly) designed for "continuous use." That alone DErates the contact amperage.

I have no idea what the time / duty cycle of a Mopar relay is