Help Please!!!! engine wont run

I had a cam and lifters wipe out before and it did the same thing you explained. I was cruising along, and it suddenly rattled, backfired, lost oil pressure and shut down. After I got it back home, tried to start it. got oil press back, but it was only to the gauge. Long story short, it punched a hole in the bottom of one lifter and it lost oil pressure from that lifter on and the valves would not open,thus keeping it from running.
I say that you check your valves to see if they are opening by rotating the engine over and watch the rockers. maybe pull the lifters out to check. Best of luck. Hope you figure it out soon.