With the looks of that motor, you have more issues than bad heads. All rusty, bent push rods, valves all stuck in the heads, What do you suppose the rings look like? They are probably all stuck to the piston. Some may even be broken. Pull out a piston, and take a picture of It. Would like to see what that looks like.
The rust mainly appears to be outside the engine, above the intake manifold, as far as I can tell in the pictures. Some fell in when he removed the intake, but it does not look too bad.
Without knowing more details, like it sat for ten years and now wouldn't start or it has been a good running truck and engine quite and now we found all the bent pushrods, my guess by the photo and brief details is that it was running, quit running when the timing chain jumped and bent valves and pushrods, and now with fresh heads and hopefully correct length pushrods, it still gas a jumped timing chain like JunkyJimmy said. Hopefully the fresh heads are not getting damaged.
