Hey everyone, truck was running pretty well until I turned it off and it didn't turn back on 20 minutes later one night. Was curious if any of you might be able to weigh in.

For context, it is converted to a Weber and I believe the PO also put in a new fuel pump by the fuel cell when swapping the carb and installing a security system (low oil pressure cuts fuel pump). It was running well enough, I tuned the carb, replaced the cat, electrical (coil, cap, plugs), and belts when I got it. It was in time. Only things I have not touched that could use some attention are the valves and probably gaskets. It has been reliable, however after a 45ish minute drive one night, I turned it off and could not get it back on to move it after. Cranks, even runs very briefly but bogs out.

I checked plugs, it was running a little rich but I am getting spark. Fuel pressure gauge is reading 2.5 psi/I think I am getting enough fuel through the line. Some potentially relevant symptoms are that the coolant level was low. No proportional puddles underneath the car, few drops at most. I flushed the cooling system somewhat recently, no leaks either. Car also does not overheat, but runs somewhat hot in the safe operating temp range in some conditions. When driving, there is a rhythmic ticking/rattling that does not increase with rpm. I assumed it was a vacuum leak but given these other developments think maybe the water pump is going bad.

Given the security system the PO put in I thought maybe something was faulty and/or cutting power to the pump or the pump was damaged, but I am getting fuel pressure and I have oil in it.

Am I due for a new head gasket/resurfacing? Any ideas? Thanks in advance.