The difference between the heads (& price) is the valve springs. Read carefully at there site. Purchase the head that best fits the current needs. When it comes time for a different cam that exceeds the spring, replace them, there cheap. You don’t want to put a high pressure roller cam spring on a lowly low lift Hyd. cam and have it wiped out.
Although you could just purchase a roller cam for the 318..... LOL... OK, not truly recommending that.
