Check your pushrods as well... A buddy of mine has broke like 4 of them lol.

 

Ok I found the problem. I feel stupid because I checked this 4-5 times. It turns out one of the valve springs is broken. It was really hard to see because the spring was broken at the very bottom, so the spring didn't look broken unless I looked really close. I noticed it because the one spring looked slightly more stretched than the others. Is it common for valve springs to break? I'm trying to find out what kind of springs I need to replace them with. I have a t-rex cam. Does anybody know what kind of springs I should use? I assume the last owner kept the stock springs when he installed the cam which is why one of them broke.

 

With stock springs and an aftermarket cam... Yes breaking springs is common.

 

I'm looking to get Crane 144832 dual springs. From looking at the pictures of the springs, it doesn't look like the stock single spring retainers will fit. Am I correct? Or should the stock spring retainers work?

 

patriot dual springs, comp springs

depends on your lift?