Just popped the valve covers on my 454 for the first time and found that the head are a 336781 casting for passenger cars from '74. The engine came from a 74 Chevelle/Monte Carlo. Just wondering if these are a good (desirable) head for a truck or not. On a side note I found the rockers were almost all loose and the front rocker on the passenger side was not even on the spring and has a very bent pushrod and broken valve guide. So looks like I have some work to do but at least there was ZERO sludge built up, they are very clean which was surprising.