Laminator_X
Once & Future KMC Hawkeye
Shazam typically has more power at his disposal than base-level Strange does. Shazam has the power of numerous gods at his disposal from the get go. Strange has to seriously power-up to achieve the level of power that Shazam has all the time.
However
Given the scenario presented here, Shazam has no chance whatsoever. None. Nada. Zilch. Strange benefits from preparation moreso than any character in comics, and I'm including Thanos in that estimate. Strange could've become omnipotent 10 times over in the timespan presented in Thanos-Quest. The scans of the Shuma-Gorath battle don't really do justice to the magnitude of that victory. Imagine that he took out one of Lovecraft's nastier alien menaces and assumed it's power, if that helps. Strange had abdorbed so much magical might that if he had returned directly to our world it would have been destroyed like a moth in a bug-catcher. There's almost no one that Strange couldn't defeat with a week 's prep. If nothing else, that's enough time to cast the 7 Gates of Chaos and destroy the universe.
In an unprepared fight on neutral ground, I'd say Shazam 3/5. If they were on the Rock of Eternity, I'd go up to Shazam 4/5. Strange still gets the 1/5 if he can absorb Shazam's energy. If he could execute a Conjurer's Sphere within the Rock, Shazam would be done, but that's a difficult move and one he seldom uses.
The scenario proposed is not a fair fight.