Need help with 4.7L -2000 dak

I have a 2000 dodge dakota that i bought about 3 weeks ago. The guy i got it from was selling it because he blew a head gasket.I believe it overheated and he kept driving it like a dumb***, to get off the highway. The result was a blown head gasket. He had it put in shop, and fixed, charged him 1100.00, but when it came out of shop, there was a weird knock/tick noise. And it kinda loud. The knock gets faster with more acceleration, but when you let off the gas, the knock fades away. It also over heated the day i bought it, so i figured the thermostat was sticking, but not sure if it is associated with the "knock" noise. I figured the rocker arms may be loose, or left loose by accident when put back together, But no. Possibly Lifters?? If anyone can help me i'd really appreciate it, because i would rather fix myself then put back in a shop. the truck is a 2000 Dak, 4.7L. with approx. 139,XXX Miles.

Thanks in advance,
Matt:evillol:

If the knock gets louder as you rev the engine, it sounds like the rod bearings are gone. Also, have the oil pressure checked. It sounds like when the previous owner let it overheat, it cooked the oil and made it useless thus causing the same affect as running an engine with no oil.