So I flushed the engine with 12qts of oil and took the car around for a nice drive about 2 days ago. Today, my friend came over and he wanted to hear the car run. I started it up and within 1 minute the car turned off. I thought maybe I forgot to turn the fuel pump on so I tried to kick it over again but the solenoid only clicked. I checked the volts going to solenoid and everything was good. Turns out MY ENGiNE CEASED!!! I cant even turn it over with a breaker bar on the crank. I drove this car for 600 miles after my rebuild without any problems and it decided to crap out at idle. I had oil pressure and I used my drill to prime the pump to 50 psi with my dewalt drill just to be sure. I removed the starter to be sure it wasnt binding to the flywheel. All valves and pushrods are fine. I didn't open the engine yet because my frustration level is at astronomical levels. How could this have happened? I'm at a lose. Can anybody please provide insight? I rebuilt the engine with all clearances in spec.