i know its a ls head, but this goes in hand with that problem you were trying to help me on. If its a b18a head, and i have the b18b cams in there, i was reading the intake cam on the b has higher lift than the a, which may be why the cam cant rotate. but ill post pic. As you can see in pic on the right is stamp, but on the left, here is where my confusion really kicks in. I know that pre 92 or 93 the bolt pattern on the IM was different, and as you can see, that freaking thing says 89. So theroretically, my supercharger should not bolt up since its for 94 and up, but, sure enough, it does. So, WTF IS GOING ON!!!