Gauges in the 1970 Chevelle

A: The 'Special Instrumentation' or 'Instrument Panel Gauge' option was not standard with any SS396 or 1969-1972 SS optioned Chevelles. Not only were they optional for the SS396 and other SS optioned Chevelles but for most years, the gauge option was available on any V8 sport coupe, convertible, and sedan pickup (El Camino).

The model years 1970 through 1972 are kind of special however. The term 'gauges' applies to a tachometer, water temperature and ammeter gauges in this explanation. For this explanation the speedometer and fuel level are not in this definition even though they 'gauge' speed and fuel levels.
1. A standard non-SS optioned Malibu (136xx) series Chevelle (as well as all other series and models of Chevelle family) received what is generally referred to as a sweep speedometer dash. A clock was a separate option under RPO U35.
Base Chevelle Dash

2. The SS-optioned Malibu sport coupe, convertible, and pickup as received round instrument pods but still no gauges; this is true for both the Z25 SS 396 and Z15 SS 454 in 1970. (Note the Z25 was dropped after 1970 and while the Z15 was retained for 1971 and 1972, it was demoted to an SS option with no specific engine designated.)  Only the speedometer and fuel level instruments were included. The fuel level gauge occupied the large left pod, the speedometer occupied the large center pod, and the large right pod was blank. A clock was still optional equipment and if/when ordered under RPO U35 the clock occupied the large right pod.
Base SS Dash

3. When the Instrument Panel Gauge option was ordered on an SS-optioned Malibu sport coupe, convertible, or pickup, the option included a tachometer, water temperature, ammeter gauge, but the clock was still a separate option.

4. When the Instrument Panel Gauge option was ordered on a non-SS optioned V8 Malibu sport coupe, convertible, or pickup, the option included the same round instrument pods and included a tachometer, water temperature, and ammeter gauge, and the clock was still a separate option.
Gauges

5. The 13857 Monte Carlo sport coupe received essentially the same round gauge pod dash as an SS-optioned Malibu sport coupe, convertible, and pickup with two exceptions. The base Monte Carlo dash still did not have the optional gauges but did have a wood grained appliqué and a clock was standard equipment.
Base Monte Carlo Dash

When the same RPO U14 Instrument Panel Gauge option was ordered on the Monte Carlo the same gauges and their locations were identical to the gauges when ordered on a V8 Malibu sport coupe, convertible, or pickup.
Monte Carlo Dash w/Gauges

Caveat - the only differences in any of the gauges supplied with the RPO U14 option was the tachometer redline range.
° 0-7000 rpm/5000 rpm redline. Used with 307, 350, and 400-2bbl cid engines (base/L48/L65/LF6) *
° 0-7000 rpm/5500 rpm redline. Used with high performance 396, 400-4bbl, and 454 cid engines (L34/LS3/LS5)
° 0-7000 rpm/6500 rpm redline. Used with special high performance 396 and 454 cid engines (L78/LS6)

* To date, all documentation shows that Atlanta installed the 5000 rpm redline tachometer in all base SS454 Chevelles (with LS5 engine) where other plants installed the 'correct' 5500 rpm redline tachometer. Atlanta did not build the Monte Carlo in 1970 so all 1970 Monte Carlos with the SS454 option (RPO Z20) should have the 5500 rpm redline tachometer along with the LS5 engine.