Just to update everyone we have pulled the old engine out! The #7 cylinder piston had a hole in the ring grove area of the piston. I had a very experienced mech tell me it was probally caused by starting fluid (Either) getting trapped in the ring grove area and on ignition weakened that area or actually made a hole. We are currently installing a rebuilt ProMar 454 longblock in the RV should be up and running Friday Afternoon? Been a long adventure but I hope the engine will add value and piece of mind in the future. Will post more as I start traveling again... Thanks to everyone! I've been an A&P for over 50 yrs never thought I'd be in this position!
