factory installed clock

Friend had 383 - 4 Bbl. 4-spd. '66 Satellite - sold it a couple decades ago for only 5 g's. That was first car I'd seen with the (front of the) console tach. Feature I liked the most was 0 - 6000 rpm's - - feature I liked the least was that you had to look way down to see it - and bulb inside better be working. But, I suppose it had to go somewhere and the cluster not set up for it.
Now I have to start thinking about what, if any, gauge will go into Swinger ralley cluster (middle).
You dont get this much info from any other gauge. VACUUM GAUGE READINGS MAGNETIC TOOL BOX CHART | eBay
"Does anyone really know what time it is? Does anyone really care?"