Re: 67 custom gauge cluster
160 mph speedo and a 10k tach....would suggest a stout build.
it's your car so put it anywhere.
As mentioned you could go to a later gauge face for 4 or any of several aftermarket multi gauge face plates.
Or, what I did, was do a 3 gauge pod (AutoMeter) bracket/gauges under the center dash. Given you swapped in dedicated speedo and tach in the 2 stock holes....you might also want, beyond fuel, oil pressure and water temp
I still have the stock 67 base cluster so went tach, OP, water temp in the 3 gauge under dash. My idiot lights are also still enabled.