I like 'em where I can see 'em. For Oil Pressure I think the Turbo block if you have it. In theory all pressures are equal in a hydraulic system so "in theory" it wouldn't matter where. In the world where I live, every passage and worse yet, corner or fitting that the fluid has to flow through or around, it encounters friction which robs it of pressure. I like to know the worst case scenario, so that, for OP I'd guess is the furthest from the Main Oil Galleys as I can get. I.E the turbo. Having said that, the Pipe Plug in the rear of the block where the Aftermarket Turbo Oil lines tap off is 1/8 NPT.
I have my H2O Temp Sender plumbed into the Left Cylinder Head at the Rear between Exhaust Valves #6 & #8, again furthest from the Radiator so likely to be the hottest. I am baffled as to why the Engineers chose the front of the Cylinder Head to locate the Overheat Switch as it is the closest Entry Point into the Head for the Coolant from the Water Pump.
You could plumb it into the 1/2" pipe port on top of the Water Pump, but that will only tell you what temperature H2O is coming from the Radiator. If you go with pulling the Pipe Plug from the head and retaining the Overheat Switch in the front of the Cylinder Head, you would be good to get a 9/16 Eight Point socket to remove it as anything else will likely round it off.
I have an Oil Temp Sender plumbed into the Rear Header of the Oil Cooler into the hole
where the 1/2" NPT Pipe plug was that was parallel with the bundle. I know that that's not the hottest oil because it's on the "cool" end or the exit of the cooler for the oil, but it is close to the temperature of the oil that the bearings will see and it's a "protected location.
Anywho, I use the head for my water temp sender. There are several ports on the corners. IIRC the stock temp sender is on the drivers head on the front lower coner.
