I am looking to the experts here for a little advice. I have been lurking here for years as I assembled my 428. Things did not go well this past weekend. I finally finished my 70 Mach 1 and got it registered and it was time to take it for its first ride. The 428 was run on the dyno at my local machine shop and it ran great with no issues. In any event, for the first test drive, I headed down the road about three miles. All was working great, good oil pressure, normal temp. I turned around and headed back home but I hit the throttle a little and took off. Little did I know at the time, a freeze plug popped out and I lost all coolant. About half mile down the road I noticed the temp starting to rise. I continued home, but the temp kept climbing and it started to knock. I made it home the 2.5 miles home not knowing I had lost all coolant as the temp gauge was not in any coolant any more. In hindsight, not a good decision. I let it cool off for a few hours and did some troubleshooting and found the freeze plug missing. Car seems to run ok, I changed the oil and oil pressure is still great, but I'm worried so I pulled the plugs and stuck a borescope in all 8. Piston tops all look good. Cylinder walls all still show crosshatching with no vertical lines. Of course it is all magnified with the borescope I used so little things look big. There were some brown spots in cylinder 4 and oil in cylinder 8. Cylinder 6 looked like it might have had oil in it too, not much though. Compression is between 160 and 180 on all 8. This seems like a big spread to me. Should I pull the heads for a better look and replace the head gaskets? What causes the freeze plug to pop out? I did use the 1 49/64" brass plugs. I hadn't planned on driving 6 miles before I had to tear it down again. What to do next???
Thanks
Jack
70 Mach 1