I bought a running and driving 55 Chevy project that was all disassembled and needs some love. Turns out the fuel in the tank was over 15 years old and it varnished all the intake valves in place which were hit by the Pistons. Pulled a couple of rocker studs. I attempted to clean without taking the heads off the car and it’s not possible. Pulled the heads and disassembled. I got everything cleaned up now I’m going back together.  DO NOT RUN ANYTHING WITH BAD FUEL IN IT!!!