National 1970 Chevelle LS6 Registry - Tech & Trivia about the LS6
The awe inspiring 1970 Chevelle SS454 with the RPO LS6 engine option was the baddest of the bad. With a factory advertised 450 HP at 5600 RPMs and 500 lb-ft of torque at 3600 RPMs, it was the highest horsepower offered from Chevrolet in any Chevelle. The RPO LS6 option added $263.30 to the required Z15 SS454 option at $503.45. Due to the 500 lb-ft of torque, the LS6 also required either the M22 "Rock Crusher" Muncie 4-speed manual transmission at $221.80 or a special Turbo-Hydramatic 400 3-speed automatic transmission at $290.40. So, right off the bat you've committed between $988.55 and $1057.15 over the base price of a Malibu sport coupe, convertible, or Custom El Camino for the experience. And what an experience it would turn out to be!
For your $503.45 for the RPO Z15 SS454 selection, you got the base 454/360HP LS5 engine, dual exhaust, a special domed hood, black accented grille, power disc brakes, sport wheels with wide oval tires, rear bumper pad (except El Camino), wheel well moldings, bright engine accents like chrome valve covers & air cleaner cover and special chassis features.
And, naturally, other options were available to personalize your LS6 such as Instrument Panel gauges that included a water temp gauge, amp gauge, clock and a 6500 redline tachometer, bucket seats, a console with floor mounted shifter for the TH400 automatic (the 4-speed was floor shifted with or without the console), a functional cowl induction hood that also included hood pins and the famous hood & deck stripe kit, Positraction rear axle, power steering and/or power brakes, tilt steering column, a selection of radios and even an 8-track stereo tape system. About the only comfort option not available on the LS6 was air conditioning.
Although the first known, documented, LS6 Chevelles were not
built until early December the wheels were put into motion at the
end of October.
October 30th, 1969
TO ALL DEALERS:
Please be advised that effective immediately, the LS3
engine for Chevelles, El Caminos, and small wagons may be submitted
for production. Also, new 360-HP SS454 option Z15 for Malibu coupe
and convertible or El Camino, may be submitted with either M40
transmission, or new option M22 4 speed special transmission. Z15
includes same axle ratio and basic components as Z25 SS396 except
engine. In addition, new 450-HP 454 engine may be ordered with Z15
as option LS6 immediately. Prices of these new options will be
forwarded as soon as possible.
In conjunction with the release of LS6 450-HP engine, the 375-HP
Engine Option L78
and the L78/L89 for use with SS 396 is in process of being
cancelled, and further orders for these options should not be
submitted.
Very truly yours,
W.C. Kuhn
Zone distribution Manager
This follow-up is generously provided by Mr. John Donchak
Fran Preve is the historian for the Tonawanda plant, I'm sure
many on here either know or have heard of him. Anyway quite a few
years ago he was authorized by GM to make copies of all plant and
dealer production bulletins from back then. He graciously did some
research for me earlier this year and confirmed a few things. Here's
pretty much the timeline based on actual internal documentation - as
opposed to the "GM did strange things" black hole of unverified
claims.
The "Richmond letter" (shown above) as it's known was disseminated on 10-30-69
from Chevy to dealers stating: "...the 375-HP Engine Option L78
and the L78/L89 for use with SS 396 IS IN PROCESS of being
cancelled..."
(On) 11-7-69 a similar letter generated from the Charleston Zone
stating: "The L78 option IS BEING CANCELLED in view of the
newly released 454 CID engines."
And finally on 11-20-69 a product bulletin stating: "With the release
of the SS 454 engines, option Z25/L78 375 HP 396 V8, and option
Z25/L78/L89 375 HP 396 V8 with aluminum cylinder heads "ARE NOW
CANCELLED".
(On) 12-8-69 A plant bulletin was released stating " The LS6
engine is now in production."
While there were certainly a small handful of Chevelles rolling
around facilities with LS6's prior to 12-8,these were R&D transplant
396 cars being emissions certified, as well as long lead press cars
being evaluated by automotive journalists etc. These were crusher
beta cars, not DOT certified, and never intended for production.
A GM exec who ordered an LS6 coupe as his zone demonstrator in Oct,
was told by the Baltimore plant manager Earl Prentice that he was to
receive the first one built at that plant, and the "Pilot" LS6 went
down the line there on 12-9-69. There are documented examples of
L78's built on 12-8, even though the RPO was cancelled on 11-20, so
obviously there was a delay involved. There are only two documented
12B LS6's known to exist, both were brass hat cars. The earliest
documented retail cars are 12C built, from at least three plants.
The pilot car is currently being restored back to exact assembly
line condition by Rick Nelson, and will be displayed at Fall Vette
Fest.
Note: As more details come to light on this car, we'll try to get
the information posted.
