After some similar failures on the old engine panel, I built a new one to fit the original mounting location on my Cheoy Lee. I used VDO gauges and now have an electronic tach with ammeter and pressure/temperature gauges with senders.

For the pressure sender you should have a connection at the flywheel end of the block that probably had a hose to the old direct operating gauge. You just need to put a brass pipe nipple long enough to clear the flywheel (or longer if it puts it in a better location) in the hole and an elbow at the end for the sender. I have an additional tee for a switch to cut off the electric fuel pump on low oil pressure. Not a big deal, any plumbing or boat hardware store will have the pieces.

It sounds like you have an old model engine with the thermostat mounted after the exhaust manifold outlet. I have a tee on manifold outlet. One side goes to the thermostat housing and the other has a reducer to fit the temperature sender. I also added a high temperature alarm switch that I put in another tee downstream of the thermostat.