history in the making, IT’S ALL IN THE HP

The 1970 Chevrolet Chevelle SS 454

Specifications

Wheelbase, inches: 112.0

Weight, lbs: 3,800

Number built: 8,003

Base price: $3,800

Model Chevelle SS LS6 Chevelle SS LS5 Chevelle SS396

0-60 Time 5.5 sec 6.0 sec 8.1 sec

¼ Mile Time 13.8 @ 98.5 mph 14.2 @100 mph 15.5 @ 90 mph

Engine 454ci./450hp 454ci/360hp 396ci/350

Source MCR MCR CarLife

Production Numbers

Malibu, convertible V6	381
Malibu, 4-door sedan V6	904
Chevelle 300 Deluxe sedan, 4-door V6	4546
Chevelle 300 Deluxe sedan, 4-door V8	5177
Chevelle 300 Deluxe coupe, 2-door V6	6119
Malibu, convertible V8	7141
Malibu, 4-door sedan V6	7525
Chevelle 300 Deluxe coupe, 2-door V8	8003
Malibu, 2-door coupe V6	12256
Malibu, 4-door sedan V8	20575
Malibu, 4-door sedan V8	37401
Monte Carlo, 2-door coupe V8	145975
Malibu, 2-door coupe V8	289622

Engine	Size		Horsepower	Torque
L34	402 ci		350 hp @ 5200 rpm	415 lb-ft @ 3400 rpm
LS5	454 ci		360 hp @ 5400 rpm	500 lb-ft @ 3200 rpm
V8	402 ci		375 hp @ 5600 rpm	415 lb-ft @ 3600 rpm
LS6	454 ci		450 hp @ 5600 rpm	500 lb-ft @ 3600 rpm

Available engines

Since first introduced -1965, Chevelle SS had grown in popularity. By the late 1960’s, the Chevelle SS with its strong faithful followers was one of the more popular muscle cars. Then every once in a great while a freak of nature occurs, something so different from the average or norm that it blatantly stands out. In 1970 the Chevelle SS LS6 was just that – a freak of nature. It was the complete apex of an era of skyrocketing horsepower ratings when it seemed like the sky was the limit, and here’s what lead to it all.

Due to an internal edict at GM, only full-size cars and the Corvette were allowed engines with displacements larger than 400 cubic inches. Because of this the 65 to 69 Chevelle SS came equipped with a 396 big block. However by the late 60’s Chevrolet got around this by allowing its Central Office Production Order (COPO) program to offer its full range of 427 V8s (including the L88) to customers who special ordered COPO Chevelles and Camaros. Though COPO allowed the production of some legendary 427 powered Chevrolet muscle cars, total production was very low. Only a few in-the-know racers and performance dealers like Yenko had used this program.

GM decided to lift the edict for the 1970 model year, and Chevrolet responded with the 454 V8 as a 1970 Chevelle SS option. The 454 is a member of the Chevrolet Mark IV big block V8 engine family. The first Mark IV engine was the 396 V8, which first saw duty during the 1965 model year. In 1966 the Mark IV 427 V8 joined Chevrolet’s engine lineup alongside the 396.

In 1970 things were only looking better for the Chevelle SS, the 454 was not only new to the Chevelle SS but also to Chevrolet. The legendary 427 big block V8 was the largest displacement Chevy V8 in 1969. For 1970, Chevrolet decided to increase the 427’s stroke, which bored and stroked reached a displacement of 454 cubic inches. The 4.25 in. bore and 4.0 in. stroke of the 454 are numbers that not only roast the tires, but also bring a smile to anyone behind the wheel.

Chevy provided two separate SS options for the 1970 Chevelle, the SS 396 (Z25) option and the SS 454 (Z15) option. With the SS 396 option one could chose from two Mark IV 396 CID V8s – the L34 (350 horsepower) and the L78 (375 horsepower). Chevy’s little secret concerning the 396 for 1970 was that it no longer displaced 396 cubic inches but rather 402. Chevy added a .030 in. overbore on the 396 block pushing its displacement up to 402 cubic inches. For some unknown reason Chevy decided it was best to call the 1970 402, a 396.

The SS 454 (Z15) a mid year option, gave the 70 Chevelle SS buyer two powerhouse V8s to choose from – the LS5 and LS6. The LS5 454 was rated at 360 horsepower in the 70 Chevelle SS, but 390 horsepower in the 70 Corvette. The reality is that the LS5 in the ’70 Chevelle SS is identical to the ’70 Corvette’s LS5. What we have here is a classic case of Chevrolet fudging horsepower figures. The 1970 Corvette was slated to have a 465 horsepower LS7 454 as its top engine option; however Chevy cancelled the LS7 before it was produced. The 1970 Corvette was stuck with the LS5 as its top engine option.

Looking back now, it’s quite clear the 1970 Chevelle SS LS6 was the Mount Everest of the muscle car golden era.