Slant six head numbers

I'm pretty sure you have solid lifters. That is a drool-tube head, which is all but guaranteed to be solids. The juice valve covers have a dent in the forward passenger corner, as shown in the photos. Since you have the engine out, the super simple solution is pop the valve cover off and look. These engines are 40-50 years old, who knows what was swapped around. As mentioned above, if the rockers have screws on them, it's a solid cam. If not, it's a hydraulic.

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