Did I toast my 340?

That area of the intake is so far from coolant that obviously something not good is up.

Here's my first take on it.
Blown head gasket sucking coolant into a cylinder close by and since it seems to be coming out right where the crossover is (that burned looking spot on the intake), the gasket is trashed right there letting oil into that crossover where it's getting mixed with coolant from the exhaust.

They may be mixing right there where they both get by that burned gasket and may not have started mixing in the motor yet. (much) :D

My bet would be a blown head gasket on cylinders 3 or 5 and the spark plug for one of those cylinders may even confirm it.

As already mentioned, a compression test is in order to confirm it.