If it's a truck block,it's not drilled for hydraulic lifters until the late fifties and then maybe only 261s. Not sure. A high water pump 235 engine will have solids unless it came out of a Power-Glide car. If somebody put hydraulic lifters in a truck engine they will not pump up at all. If somebody put in a hydraulic cam with solid lifters, it will be very noisy.
I was in a jam once (1978) and hired someone else work on my truck, replacing a cam ruined when the fiber cam gear let go. They put in a hydraulic cam because that's what they had lying around. It was way noisy at solid lash spec. After I got tired of keeping the lash to 0.002 so I could hear myself think, I bought a set of hydraulic lifters to put in. That didn't work at all because the lifter gallery wasn't drilled for oil pressure. I ultimately had to install a solid lifter cam with all that entails (remove radiator, grille, timing cover etc.). That ran for about 20 years until I put a hotter cam in.
