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.

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.

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 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.

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.

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.

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.