Perfect reason to get a modern gauge. Either digital or the old mechanical/direct type. One of the first mods we did in the 60/70s was to replace the stock stuff.
A lot of things effect the running temp. Obviously a 70 car didn't come with a 360. So was it a used 360 that was just put in with no mods/upgrades ? Likely not, so what is the rest of the story....
What mods, timing, compression, a/c, exhaust, carb type, type/size radiator, fan, clutch type, shroud, thermostat type/degree, coolant type/% , radiator cap lb rating, ....
Modern cars run in the low 200°-210° range.
Idling, driving , speed all effect temp. Middle of the gauge may be fine or not since you don't know what the actual temp is just like you never really know exactly how much gas is in the gas tank, just an approximation that changes as the gauge goes up or down not at the same rate.