I wont know for a week or so what happened, I have too much work to break for the truck. I was in the middle of a return trip from SkiGirl's build up this weekend working through the night and commuting home when about 4am the truck overheated. I had noticed the temp guage had stopped working and said zero so I pulled over in Riverside and checked the guage, and all the fluids (first bad sign /forums/images/graemlins/ears.gif). I found the coolant a little low and filled it, then turned the heater on high and continued on. About half way between Riverside and Lake Elsinoire in the middle of nowhere, the truck started pinging and running a little rough so I quickly pulled it over (second bad sign /forums/images/graemlins/1zhelp.gif). It was 5am, dark, no cell phone (perhaps no service anyhow) cant find my flashlight and obviously over-heating from the steady flow of steam coming out of the radiator overflow bottle. Having a little foresight, I made sure I had 2 jugs of radiator fluid back in Riverside. I knew I was expected to get home in time take to take my boy to school in the morning so I pulled my lever-vent radiator cap ( a new addition before I left and a must in my book now over the simple twist kind). Once things cooled down a bit, I added the two jugs and realized I didnt have enough and had no obvious leaks (third bad sign /forums/images/graemlins/thinking.gif). The truck started rough but the temp guage started working. Given I'm in nowhere, my truck has $7000 of fabricating gear in it with the tube doors and no roof, I wasn't about to leave it for any reason, so I worked my way to the nearest anything. About 5 minues later with everything seeming to go well, the temp starts rising so I pull it over again, same steem. Now its getting light so I ran some basic diagnostics, pulling plugs and found that the number 8 piston has a slightly cleaner plug and when cranked would spray oil/water foam. Thanks to my T-cap style valve cover bolts, I quickly locked the intake closed and exhaust open on the number 8, filled the radiator with Lake Elsinore stream water and drove it to a gas station which eventually had water and a phone. Coolant level was still good but the engine was running alittle rougher than just the missing number 8. I ended up working the truck a ways closer to home with adding coolant every time it overheated and after 5 hours, eventually got it home. I figure the rotating assembly is all good, maybe a cracked bore into the water jacket, maybe a cracked head across the intake and exhaust or hopefully is just a blown head gastket and a mill of the heads. I have a lot of faith in this 415 rotating assembly so I'm no too worried there, speedomotive makes a great product! I do have a set of heads on there which I hadn't manafluxed before the headwork so anything goes there. I'll post on what I find, when I can get to it. Cross your fingers!