Hey Scotty, I have a 1998 GMC 1500 Z71 5.7L that is my work truck and in general my only vehicle. Im very dependent on it. I was pulling a large hill leaving Reno Nevada while being loaded with maybe 500-600 extra pounds. it started making a bad ticking sound coming from the head and I lost a lot of power. I had to limp it home another 60 miles away. I pulled the valve cover and found a bent push rod on the number four exhaust cylinder. THE ROCKER ARM NUT HAD BACKED OFF. I Installed a new push rod and adjusted it. It still runs the same tho. It's not smoking. It doesn't have any terrible noise, it just sounds like a dead hole. It keeps popping the cylinder 4 misfire. The only thing I can think of is that I bent a valve. What would you do from here? Buy a new head? Buy a rebuilt motor? Pull the head and see exactly whats going on? I know this truck is old but I love it and I've put a lot of money into it to keep it in the best shape possible. What would you do? Please help! Thank you! 

Also, it never overheated. The oil and coolant all looks good.