I just picked up the original Rocket 350 for my ‘71 Cutlass. The previous owner never had the engine in the car and was told by the owner prior to him that one of the plugs was continuing to foul out. I pulled the intake off tonight, pictured below. It looks normal but there are some darker spots. Also I pulled the one value cover off and two rocker arms were missing. So someone has been playing around with the engine.

 

Thats about as far as I got on my 330 using air pressure to change valve guide seals when I realized it had a blown head gasket.