Tonight I was giving my friend a ride in my Bullitt I just purchased a few weeks ago. I ran the car up to about in 5800-5900 rpms in first and shifted and when the car reached around 4500 and 5000 in second the car fell on its face so I let out. When I put the car back into gear it was missing on one cylinder. I'm pretty sure I bent a valve. What should I upgrade as far as valves and valve springs and also what brand. Should I upgrade both or just one of them. I am new to the 4.6 engines so I don't really know their weak points. I knew the connecting rods and pistons were weak but I dont know anything about the top end of these engines. The car has a ATI P1SC on it running 7 #s. The car put down 360 hp under load during tuning on a dyno.