Originally Posted by Tx Benz

Concur with Bribenz

Pull both valve covers, wiggle rocker arms.
Each one you can move with your fingers==bent valve.
Note --there could be other damage.
Pull the heads, check for cylinder scoring.
Have seen valve head break off, lodge in piston, gouge cylinder wall.
One put the con rod through the side of the block. Ugly.

9 of 10 times, however, valve job on BOTH heads(mileage) and chain and rails
gets you going.
We do them with engine in the car.
Helicoil head bolts if heads are removed(takes special jig-plate)