FEATURE ARTICLE from Hemmings Muscle Machines
Chevrolet El Camino SS454 1970-72
Hemmings Muscle Machines - JANUARY 1, 2005 - BY MARK J. MCCOURT
When is a truck not just a truck and a muscle car much more than a muscle car? When they're an El Camino, of course. Chevrolet's third-generation "personal truck" mirrored the A-body Chevelle upon which it was based and shared engines and equipment, and when fitted with ultra high-performance SS454 equipment, the 1970-1972 El Camino could run rings around many conventional muscle cars while retaining a semblance of truck utility. Like Chevelles, El Caminos are blessed with an amazing availability of restoration and performance parts, and they appeal to folks who love big-block power, who need utility beyond what a coupe or convertible can offer, who appreciate the El Camino's "neither here nor there" style, and who don't like to see their doppelgängers at every stoplight. The Chevrolet El Camino SS454 truly inspires bowtie pride while hauling from both ends.
The El Camino had been completely restyled for 1968 along with its platform-mate Chevelle; this early "crossover" vehicle's airy greenhouse and slim B-pillars were made sportier with thick B-pillars that curved down as flying buttresses to meet and envelop the leading edge of the bed, which now measured 79 1/4 inches long and 59 to 64 1/2 inches wide behind the cab and at the tailgate, respectively. The truck had a handy storage area inside the rear of the passenger compartment that enthusiasts have dubbed the "smuggler's compartment." A plastic toolkit box was stored in this area, and behind that, under the bed, was an unutilized area where the Chevelle wagon's rear seat footwells remained in the shared floorpan; the El Camino's spare tire was stored upright behind the passenger seat for easy access.
This truck's front-end styling was modified when the 1970-1972 models arrived, although the new trucks were identical to the 1968-1969 models from the firewall back, save for minor trim. The 1970 restyle brought quad headlamps set in a body-colored surround panel, which framed a bold horizontal grille split by a body-colored bar. Circular parking lamp/turn signals were mounted in the front bumpers, and SS grille and fender badges and a standard domed or optional cowl-induction hood were part of the Super Sport package. The $2,850 V-8-powered El Camino Custom was the basis for RPO Z15/LS5 and RPO Z15/LS6, which translated to the new SS454 and eclipsed the previous top-performing SS396. This $503.45 Z15/LS5 package brought a 360hp 454-cu.in. V-8, chrome engine accents, dual exhausts, power front disc brakes, a black painted grille, chrome wheel-arch moldings and 14 x 7-inch styled steel wheels. Adding the $263.30 Z15/LS6 package netted the famed 450hp LS6 V-8, making the 1970 El Camino the hands-down fastest truck on the planet. The aforementioned cowl-induction hood was part of the $147.45 ZL2 package, which included a sport-striped, pin-secured hood with a vacuum-operated flap that ducted low-pressure cold air to the carburetor when the accelerator was floored.
As was typical of Detroit in the muscle car heyday, the El Camino SS454 received some changes each year; new for 1971 were fender-mounted two-part turn signals flanking single round headlamps, and the grille was restyled with a single thin chrome center bar. Hood pins became standard, and sporty new dark gray 15 x 7-inch road wheels with chrome trim rings were shared with the Camaro; revised vinyl upholstery patterns enlivened the interior. This year, a subtly retrimmed GMC version of the El Camino called the Sprint was a fresh offering, and the hottest Sprint SP-454 was a virtual clone of the SS454. In 1972, the El Camino received one-piece front turn signals and a grille with two slim horizontal chrome bars. Despite being only 200 miles from new, an LS5 El Camino SS454 was a lively performer, as noted by Drag Racing USA in February 1971: "The quarter-mile performance was frankly better than we'd expected with this new low-compression version of what had been a high-compression engine. Our e.t.s averaged 14.7 seconds at speeds of 96 to 97 mph.... Given a few hundred more miles and sharp tuning, we see no reason why two or three tenths, at least, wouldn't come off the e.t."
Because Chevrolet lumped all of their A-body vehicle build numbers together in the early 1970s, the high-performance El Caminos and Chevelles were merely separated by the engines under their hoods. Of the 8,773 SS454 El Caminos and Chevelles built in 1970, 4,298 featured the LS5, and 4,475 had the LS6 engines. In 1971, SS454s in both models featured the LS5 V-8, and 9,502 were built; 5,333 LS5-equipped SS454s came off the line in 1972. The aforementioned GMC Sprint SP-454 was considerably rarer, with 25 built in 1971 and 114 in 1972. As with red-hot and valuable Chevelle SS454s, the El Camino SS454 invites cloning; be sure to authenticate a potential purchase by cross checking VINs on cowl tags, Protect-o-Plates and other engine and body stampings.
ENGINES
The El Camino SS454 didn't get a lion's reputation by having a housecat under the hood; nestled between its fenders in 1970 was one of two big-block 454-cu.in. V-8s that shared a 4.25 x 4.00-inch bore and stroke and five main bearings. RPO LS5 translated to a hydraulic-lifter version that produced 360hp at 4,400 rpm and 500-lbs.ft. of torque at 3,200 rpm via a 10.25:1 compression ratio, Rochester four-barrel 4MV Quadrajet carburetor and dual exhausts. Highest on the food chain in 1970 was the coveted LS6; despite having the same displacement as the LS5, it made a Hemi-whipping 450hp at 5,600 rpm and 500-lbs.ft. of torque at 3,600 rpm. This feat was accomplished with solid valve lifters working larger, 1.88-inch exhaust and 2.19-inch intake valves, 11.25-compression, a more radical camshaft and an 800cfm Holley model 4557 or 4150 four-barrel carburetor. Sadly for ultimate muscle enthusiasts, this engine was not installed in El Camino SS454s (or Chevelle SS454s) in 1971 or 1972.
A drop in engine compression from 10.25 to 8.5, and a switch to regular fuel didn't stop the LS5 from gaining 5hp in 1971 due to redesigned combustion chambers-this, in the year when real world SAE net figures replaced the previously favored test lab gross numbers. Despite the predisposition of advertisements to call out the stronger figures of 365hp at 4,800 rpm and 465-lbs.ft. of torque at 3,200 rpm, the government now preferred that the LS5 report its 285 net horsepower at 4,000 rpm and 390-lbs.ft. of net torque at 3,200 rpm. Although the engine carried over intact in 1972, its horsepower figure dropped slightly to 270hp at 4,000 rpm. California residents were not invited to the LS5 party in 1972 due to new emissions regulations, but creative 49-state residents could skirt the system and order LS6 heads and other components at the parts counter of their friendly local Chevy dealers. In today's muscle car restoration market, the Chevrolet V-8s are second to none in replacement parts availability, and Chevrolet and a number of suppliers even offer complete 454-cu.in. crate engines.
TRANSMISSIONS
Like their Chevelle siblings, many 1970-1972 El Camino SS454s were built with the optional M40 Turbo Hydra-Matic three-speed automatic transmission. If the buyer of a 1970 LS5-equipped SS454 wanted to shift for himself, he used the standard Muncie M21 close-ratio four-speed gearbox with its single dry-plate 11-inch clutch, or he could order the heavy-duty Muncie M22 four-speed that was used if he ordered an LS6 El Camino. Manual gearbox buyers in 1971 and 1972 were automatically treated to the M22; all El Camino transmissions are hearty units that have proven themselves, and repair and refurbishment are easy with their many suppliers and specialists.
DIFFERENTIALS
The 1970 El Camino SS454 used a 12-bolt open hypoid differential with a standard 3.31:1 ratio, and a limited-slip Positraction unit using the same ratio was a factory option. The 3.31 ratio was continued in 1971, when an optional Positraction rear with a 4.10:1 ratio became widely available; Chevrolet simplified the option sheet in 1972 by dropping the Posi/4.10 combination. All of these 12-bolt units have earned bulletproof reputations, and replacement parts or Positraction upgrades are easily acquired.
SUSPENSION
The El Camino shared its A-body suspension setup with the Chevelle wagon upon which it was based. In front, the independent suspension utilized upper and lower control arms with ball joints, heavy-duty coil springs, hydraulic tube shocks and a 1.25-inch diameter anti-roll bar, and in the rear, upper and lower control arms, coil springs and level-control air shocks kept the solid rear axle off the ground. "The 1968-1972 SS package for the El Camino contained everything that was in the SS package for the Chevelle, with one exception," says Dan Carr, El Camino tech advisor on the A-body specialty website www.chevelles.com; "The F41 heavy-duty suspension, with its rear anti-roll bar, was never available on the El Camino, even the SS454...it's believed that this was prohibited due to the hauling nature of the vehicle." Any worn or damaged suspension equipment is easily replaced with stock components.
BRAKES
The standard four-wheel hydraulic drum brake system used on base El Caminos all three model years was supplanted on SS454 models by a standard front disc/rear drum setup. The 10.94-inch front discs with single-piston calipers and 9.5 x 2-inch rear drums could be augmented with optional power assist. All brake parts are simple to acquire, and upgrades are easy using newer stock GM components.
FRAME
The 116-inch wheelbase that all 1970-1972 El Caminos utilized came courtesy of their boxed-rail perimeter frames with welded front and rear cross-members. This heavy-duty frame was shared with station wagons and is interchangeable with those underpinning 1968-1972 wagons and El Caminos. Check out the body mounts and differential mountings by the rear suspension control arms for rust, as frame rust is repairable but pricey.
BODY
Despite their sporting intentions and luxurious interiors, many El Camino SS454s were parked outside, did light-duty hauling and were generally treated like trucks. As with any vehicle more than 30 years old, rust can be an issue. "Typical rust areas include the lower parts of the front fenders where leaves and debris get trapped, around the rear window if the truck came with a vinyl top, around the rear wheel wells and in the lower rear quarter panels," Dan says. The hidden storage area behind the "smuggler's compartment" is often not waterproof and traps water and debris under the bed, leading to rust. Luckily for El Camino owners, many body panels are interchangeable between 1968-1972; Chevelle wagons can donate their front fenders from 1970-1972, hoods are shared between all Chevelles and El Caminos, 1970 front bumpers are shared with Monte Carlos, and doors can come from 1969-1972 El Caminos. New reproduction doors, full and partial fenders, rocker panels, tailgate panels and bed floors are readily available from a number of reputable suppliers.
INTERIOR
Although manual or power-adjusted Strato-bucket seats and a center console were optional in El Caminos as in Chevelles, the standard bench seat (allowing more than two passengers) was more often used. The standard all-vinyl interior used Madrid grain in 1970; and in 1971 and 1972, Madrid grain bolsters were teamed with Elk grain inserts. The vinyl door panels in El Camino Customs differ from those in base El Caminos, but they are commonly reproduced; dashboard instrumentation was shared with Chevelles and contemporary Monte Carlos and the standard warning lamps could be replaced by a tach and accessory gauges. Among the multitude of reproduction interior items available are dash covers, carpeting, seat covers, seat foam and switches.
REPRODUCTION PARTS
Prospective El Camino restorers should count themselves lucky to be tackling a vehicle that has such a strong restoration parts supply; because these 1970-1972 trucks share so many mechanical, body, chassis and trim components with contemporary Chevelles and earlier 1968-1969 El Caminos, nearly everything is being reproduced. El Camino parts specialists and Chevelle/GM A-body suppliers can offer everything from pistons, camshafts and smog pumps to quarter panels, seat covers and road wheels. El Camino-specific reproductions such as 1971-1972 headlamp bezels, bed trim, tailgate trim and taillamps can also be readily purchased, as well as SS454-specific striping kits, trim and mechanical components-this is one vehicle that rarely requires trips to swap meets or salvage yards for parts. Rudolph Wichmann, the owner of our feature truck, told us that he's been unsuccessful in finding the gasket that underpins his El Camino's original remote rearview mirror-"Everyone has something close to it, but they're all off by a bit here or there." If a part simply can't be purchased new, locating an earlier El Camino helps with body and trim from the firewall back, and contemporary Chevelle station wagons can offer front sheetmetal, frames and interior parts; other A-body cars like Buick Skylarks, Oldsmobile Cutlasses and Pontiac LeManses can also donate suspension, braking and under-the-skin components.
PERFORMANCE PARTS
The El Camino is like its Chevelle brethren in that its V-8 performance is easily upgraded. Whether you're looking for hidden internal upgrades like forged pistons, hotter camshafts or hardened valves for a matching-numbers engine, or external upgrades such as high-flow carburetors, free-flowing headers and exhausts, aluminum intake manifolds and cylinder heads and ignition system upgrades, you can find them at a number of reputable parts suppliers. Complete crate engines with huge power upgrades are also available from GM Performance Parts for those unconcerned with originality. Transmission, clutch, torque converter and differential upgrades are also just a phone call and some wrench time away.
CHASSIS UPGRADES
Just because the SS454 has a pickup truck bed, this doesn't imply that it can't be made to handle more like a sports car; most of the suspension and braking upgrades that are available for Chevelles will simply bolt on to an El Camino. Starting from the ground up, a set of H- or V-speed rated performance radials on wider SS rims from Wheel Vintiques or retro-style light alloy wheels will keep the truck planted; suspension upgrades include fitting a larger front and a new rear anti-roll bar, installing Moog's adjustable tie rod ends, Global West's negative-roll front control arms, lowered coil springs and stiffer urethane bushings. Replacing the hydraulic front shocks with gas-charged units and upgrading the rear air shocks will also help the truck stick. Burn off that newfound speed with some retrofitted GM brake components like B-body spindles mounting F-body front discs, and rear discs can come in a kit from Stainless Steel Brakes or Ground Up. Keep the performance coming, and blur the distinctions between truck and car even further.
Owner's View - Rudolph Wichmann, Jr.
"When I graduated from high school, I was driving a 1970 Chevelle SS454 LS6," reminisces Rudolph Wichmann, Jr. "When I got it, I had the choice between that LS6 or an El Camino SS454, and I've wanted one ever since then." Rudolph found his one-owner truck in storage, where it had sat for 15 years. "I wanted a true 1970 SS454 El Camino, and this one had matching numbers and a lot of options, including factory air. I had to replace one quarter-sized spot of rust, but the rest of the car was solid. I repainted it in the original Autumn Gold, reupholstered the seats, headliner and carpeting, and had the transmission rebuilt and the engine bored .030-over-the car was pretty much all there." And Rudolph couldn't be happier with the results. "It drives like a new car coming off the showroom floor," he says. "The column-shift automatic shifts smoothly, the steering, shocks and suspension are great, and it's very fast... I get a lot of thumbs up on it." So does he work the El Camino like a truck? "I use it strictly for showing. I don't haul anything back there except for the chairs I sit on, and when I have the bed repainted gold, I probably won't put anything in the back," he explains-not even the matching diecast model that displays with his truck. Such is the world of a self-professed SS454 junkie. "I like the El Camino because it's different," he smiles, "Not like any other car or truck on the road."
This article originally appeared in the JANUARY 1, 2005 issue of Hemmings Muscle Machines.
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