Chevelle LS6. King of the hill. The fastest, nastiest, most powerful car of the muscle car era. Last gasp or triumphant announcement that horsepower was king? With perspective it’s easy to see why 1970 was the pinnacle of the muscle car era, but at the time, did they know the end was near? I suppose that’s why guys like Walt Promies bought cars like these—have fun now and let the future take care of itself.

The quick summary is that this remarkable 1970 Chevrolet Chevelle SS 454 LS6 hardtop is quite likely the most authentic unrestored LS6 available anywhere. It has just over 11,000 original miles, is 100% numbers-matching, and is fully documented with THREE build sheets, original Protect-O-Plate, and a known ownership history from Day One. It has been freshened and maintained, but never restored, and currently wears its original paint, interior, and trim, and carries its original LS6 engine that has been freshly rebuilt. It will be very, very difficult to find a better LS6 than this.

In October of 1969, a young fellow in his ’30s by the name of Red Armstrong was an avid car guy, street racer, bench racer, and small airplane pilot. He was reading the Wall Street Journal, which featured an article about how General Motors was about to introduce the biggest, most powerful street motor ever offered to the public, the LS6. With 454 cubic inches and 450 horsepower in the 1970 Chevelle, it would unquestionably be the fastest American production car you could buy. He was hooked.

Red would hang out with three other like-minded friends with similar interests, including this car’s original owner Walt Promies. With Red’s prompting, they all agreed to buy new LS6 Chevelles the moment they were available. In early November 1969, all four young men went to their local Chevrolet dealer to buy four new LS6 Chevelles. The salesman they talked to had no knowledge of the LS6 option and wanted them to stop wasting his time because he didn’t believe these four men could afford four new Chevelles. So they left and went to Sheffler Chevrolet in North Olmsted, Ohio on the far west side of Cleveland. The salesman there was more than happy to sell four cars at one time with whatever options the buyers wanted. In fact, the salesman was so grateful for the order, he took all four of his new customers to a local men’s club for dinner and drinks for the entire evening.

The men ordered four LS6 Chevelle hardtops, two in Shadow Gray with no stripes, one in LeMans Blue with no stripes, and this Forest Green car with white stripes. The thinking was that the stripes would attract the police, but Walt liked the look. The green car and the two gray cars were automatics with a bench seat and column shift (in the interest of light weight), while the blue car was a 4-speed with buckets.

That year, the four men raced on the streets and on the runways at Red’s airport—no rules, just make your car faster than the other guy’s. The only modification that was consistent for all four cars was the high-beam headlights. Since Red worked at an airport, he retrofitted all four Chevelles with the landing lights from a commercial airliner and used a relay to keep them from cooking the wiring. These aren’t just bright, they are melt-your-eyeballs-out-of-your-head bright. Perfect for racing in places where you don’t want to be seen.

Today, this Forest Green car shows 11,679 original miles, largely due to the fact that it was only used on weekends as a toy. It has a known ownership history starting with original owner, Walt Promies, who sadly passed away not too long ago. He did all the mechanical upgrades for racing when the car was new. A few years after the group stopped racing, Walt sold the car to a local couple who half-heartedly raced the car but eventually divorced and the car was sold to its third owner, Tim Blevins. Tim wanted a trailer queen show car, so he took the very clean, low-mileage Chevelle and covered the engine with chrome and painted the undercarriage with gloss black Imron. The car was displayed without a hood and given its status as a show piece, the fact that it was a full race motor didn’t really bother anyone. In 1983, Randy Becker purchased it in show car condition and decided he wanted to take it back to stock—Walt’s rather extensive modifications, including aluminum heads, some sort of fuel injection system, and a giant cam, made it a bit of a handful on the street. Randy quickly found that to be easier said than done and complained that every time he drove the car, he would be targeted by the police. Eventually he parked it. However, Randy had the foresight to contact Walt Promies, who was still alive and overjoyed that his old Chevelle was still around and not crushed into a cube. Remarkably, Walt still had almost all the parts he’d removed from the Chevelle 13 years earlier, including carburetor, heads, intake manifold, exhaust manifolds, and more, and he was more than happy to reunite them with the car. Unfortunately, Randy never got around to returning it to stock spec, and it sat in his garage for more than 35 years.

In 2018, the most recent owner, a noteworthy Chevrolet collector and Chevelle expert, heard about this low-mileage LS6 in a suburban garage and managed to acquire the car and all the parts. He embarked on a mission: return it to original specification. The engine, transmission, and rear end—all original, matching-numbers pieces—were rebuilt and the 4.56 gears were swapped back to 3.31s. The engine bay was detailed for show and all the original accessories were reinstalled, including the original carburetor, water pump, power steering system, and manifolds. Correct finishes and hardware were used throughout, although the fact that the car had likely never seen rain, never mind snow, made much of the job easy—even the original tar paper flaps on the front suspension are still 100% intact!

Here are all the relevant details on every single critical component on this incredible LS6:

VIN
136370K145045
(145045 is visible in block 9, upper right corner of all three build sheets)

Cowl tag
ST70: 1970 model year
13637: Malibu Sport Coupe
KAN: Kansas City, MO assembly plant
451861: Fisher body number (matches block 8 & block 24 on build sheets)
TR 755: Black vinyl
48 B PNT: Forest Green with black vinyl top
12D: Assembly date (fourth week of December 1969; actual build date December 22, matches block 10 on build sheet)
0100: Data processing numbers (matches block 24 on build sheet)
1: Day of production week (Monday)
L: Malibu Sport Coupe

Protect-O-Plate
136370K145045 (VIN)
H: Carburetor source (Holley)
T1211RR: Engine assembly code (T = Tonawanda assembly plant, 1211 = December 11, 1969 assembly date, RR = LS6 with TH400 automatic transmission, matches engine stamp pad)
RV1212B: Rear axle code (RV = 3.31 Posi 12-bolt LS5/LS6, 1212 = December 12, 1969 assembly date, Buffalo plant, matches axle stamp)
D: Build month (December 1969)
70Y328: Transmission code (70 = 1970 model year, Y = TH400 for LS6, 328 = assembly date November 25, 1969, matches transmission identification tag)
1133: Option codes (1 = power steering, 1 = power brakes, 3 = radio, 3 = disc brakes)
Vehicle delivery date: January 10, 1970

Engine
Casting no: 3963512
Casting date: K26 9 (November 26, 1969)
Casting code by oil filter: K HI PERF PASS 1
VIN stamp: 10K145045 (matches VIN, stamped upside-down which is correct for Kansas City assembly plant)
Assembly stamp: T1211CRR (December 12, 1969, LS6 with automatic transmission)

Transmission
Matching partial VIN (10K145045)
Identification tag:
328 = Assembly date (November 25, 1969, 328 days after January 1, 1969)
70 – CY – 1221: 70 = 1970, CY = TH400 for LS6, serial number 1221
Rear axle Tube stamp CRV 1212B1 (CRV = 3.31 Posi 12-bolt LS5/LS6, 1212B1 = December 12, 1969 assembly date, Buffalo, 1st shift, matches Protect-O-Plate)
Casting no.: 3969278N (12-bolt casting)

Carburetor
3969898-GR (GM part number, correct for LS6 TH400)
LIST-4492 (Holley part number, correct for LS6 TH400)
9B2: Assembly date (second week of December 1969)

Intake manifold
Casting no: 3963569 (correct for LS6)
Casting date: not visible without disassembly

Exhaust manifolds
RH 3916178 (correct for LS6)
LH 3909879 (correct for LS6)

Alternator
Inconclusive

Water pump
Casting no: 3969811 (correct for 1970 LS6 454)
Casting date: H19 (August 19, 1969)

Distributor
Inconclusive, unable to photograph

Coil
(1115)293 B-R (correct for 1970 LS6 454)

Starter
1108430 (correct for LS6 454)

Battery
R59S (top terminal battery is correct, see block 49 of build sheet)

The rest of the car needed nothing but cleaning. The original factory-applied code 48 Forest Green paint is almost as new, and, in fact, we have a letter from owner Randy Becker to the president of the Chevelle club complaining that he was tired of all the “experts” telling him that the car HAD to be a repaint because it was so nice. However, we note that all the readings on a paint thickness gauge are between 3 and 5 mils, with nothing over 8 mils, which surely indicates factory paint. In addition, there’s a little tiny “mistake” on the deck lid stripes, which could only have been done by the factory—no self-respecting body shop would allow a mistake like that to go out the door. All evidence points to this being original paint on this incredible Chevelle. Likewise, the black vinyl top is also completely original and in spectacular condition. The chrome and stainless trim has never been removed and shows almost no wear or signs of age.

The only non-stock parts on it today? Those high-output landing lights as high-beams, but who would want to erase that little bit of history? Too cool!

The original black bench seat interior was removed and cleaned, and while it was disassembled they found not one, not two, but THREE completely intact, legible build sheets: one behind the back seat, one in the passenger door panel, and one in the dash. In addition, they found the original headliner trimmings from when the headliner was installed on the assembly line, as well as a 1969 dime and a Bazooka Joe gum wrapper. Talk about an untouched car! The upholstery remains almost new, with the front seat still just as firm as it was when Walt and Red were racing late at night. The carpets—original carpets—are not worn or faded. The dash pad is supple. There’s not even a depression in the driver’s armrest where Walt might have rested his elbow while cruising. The optional U14 Rally Gauges are all operational and it carries its original 6500 RPM LS6 tach. Everything works except the clock, and the radio powers up but does not pull in stations which is likely due to a broken wire from the windshield-mounted antenna (the windshield is original, and you’d be crazy to replace it to make the radio work). In the trunk you’ll find factory-applied spatter paint, original trunk mat, and the original spare tire that looks like it has never been used.

The original, matching-numbers 454 cubic inch V8, better known as the LS6, was fully rebuilt with machine work and dyno tuning by Badman Racing Engines. Dyno sheets show a rather stout 463 horsepower and 512 pound of torque, right in line with what a proper LS6 should be making. This is unquestionably the car’s original engine, with a correct date stamp, suffix code, and partial matching VIN on the stamping pad. It is most certainly NOT a restamp or a forgery and it has its credentials in order. It starts and runs superbly, and is surprisingly docile for such a monster of a 1970 powerplant. Even the mechanical valvetrain is quiet and well-behaved. It’s savagely fast, I’m sure (with only a few hundred test and tune miles, it’s not yet time to hammer on it), but it also just works like a car should work. Easy starts, nice idle, smooth power, no fussiness in traffic. Impressive.

At the same time, the original, numbers-matching TH400 3-speed automatic transmission was rebuilt and Walt’s racing torque converter was replaced with a proper unit that’s a bit more tame. Out back, the 4.56 gears they used for racing were replaced by original-spec 3.31s on a fresh Posi, and yes, that’s the original rear end housing with correct date codes. The original suspension, brakes, and other details were untouched, albeit serviced—the master cylinder and brake calipers were rebuilt, not replaced, there are new flex lines, and a fresh gas tank hanging out back. The floors are unmarked, still covered in shiny Imron from the guy who thought he’d turn it into a show car. A bit of a shame that it’s not quite original, but it sure looks tidy under there. It also carries a fresh Gardner exhaust system with correct stamping codes, which cost several thousand bucks all by itself. The non-stock bits are the rear air shocks, but that’s easy enough to remedy if you want to correct that little bit of its past life. 14-inch SS wheels carry reproduction F70-14 Goodyear Polyglas tires for a proper 1970 look.

Documentation is obviously very extensive. The car includes all three build sheets, the original Protect-O-Plate in Walt Promies’ name, original owner’s manual, previous ownership history, correspondence, invoices, service receipts, dyno sheets, an appraisal from 1986 when the car showed 11,124 miles, and much more. This car has a bulletproof pedigree.

Please review the photos carefully, because this is an extraordinary find. Few Chevelles are more correct than this one and thanks to the low mileage, it remains in exceptional condition. For the enthusiast who seeks the best, this car will measure up in every way that matters. It’s sorted, it’s correct, and the paperwork backs up everything we’re telling you. You will look for a long time before finding a better LS6 Chevelle than this. Call today!

Harwood Motors always recommends and welcomes personal or professional inspections of any vehicle in our inventory prior to purchase.