Big problem

[C. M. Wolf]

Oh yeah.. it sounds really 'not good'... and not cheap either.

Causes... ? Oil got too low and quit pumping, broke an oil pump & quit pumping oil, or lost oil through some kind of bad leak,(possibly a road impact of some kind, CA freeways are real good for that).

Anyways, the grinding was likely engine bearings far overheating & welding themselves together with friction... or in other words, I think your Chevy had a heart attack on the freeway... but the good news is.. a new engine can fix it again.

It could have been worse, I've seen hotrod Chevys go through something similar and the engine throw rods & pieces of heads through the hood at pretty high speeds... it doesn't sound like you'll have to do a lot of bodywork too..

Michael