100 Dollar Hemi!

I just picked up a Hemi out of a 2011 truck for 100 bucks Canadian so like 75 American! The guy said it was running rough so they replaced it without checking what was wrong! Initial inspection looks good so far but I only had time to take off the valve covers and one head! I know the lifters are known to go bad so that's what I was going to check first! Any other reasons it would run rough that anyone can think of? Either way I was willing to take the bet for just 100 bucks! Lol