Briggs and Stratton OHV single with bent push rods: DOA or Salvageable?

I picked up a free snowblower yesterday. The owner said it was locked up.

It has a Briggs and Stratton OHV engine. I was able to get it to turn over, but not smoothly. I tried the electric starter, but it sounded awful.

I exposed the electric starter. It was stuck open, with the drive gear engaged with the ring gear on the flywheel, so I removed it completely.

The oil was full, but ugly and there was a lot of black crap on the spark plug. I added a little Marvel Mystery oil down the spark plug hole and was able to get it to turn over with the plug out.

I drained the oil, and it looked like a mochaccino. I refilled it and then redrained it and I think I got most of the nasty stuff out. I refilled it again, added some starting fluid and still couldn't get it to fire. Finally, I removed the valve cover saw that the intake valve was opening, but not the exhaust. Closer examination revealed that the intake pushrod was bent and the exhaust valve was stuck closed. I loosened the exhaust rocker and found that its pushrod was bent too. That's when I quit for the day.

So is this engine trashed or can I try to knock the exhaust valve loose, add some new pushrods and expect it to run?

Harbor freight time

Get another engine, the one you have sounds like it is toast. 

Get new pushrods. What do you have to lose. I replaced a bent pushrod in my v-twin kawa 17hp. Mine was caused by backfires. I imagine a chipper might see some load shocks which could do the same thing.

Same on pushrods. Also, check the Vavle lash as well.

The pushrods bent for a reason. Likely the valves are seized in the head, so the head needs to come apart.

I've had an 11hp B&S Intec snowblower motor apart and found the valve springs are soft enough to push open by hand.  If you can't move the rockers enough to open the valves, then something is seized.  Either the valve is stuck in the guide or rusted to the seat.  I'd check the condition of the crank, rod, and cam bearings before putting much effort into the motor.  If they are good, look into what's wrong with the valves and go from there.