Build #4 Naturally Aspirated Delivered

1970 CHEVY CHEVELLE

Old-school big-block soul — 454 cubic inches of ATK Performance under the cowl-induction hood, Holley Sniper EFI for cold-start reliability, TREMEC TKX 5-speed shifting the lot.

Pensacola, FL · Mad Labs Performance HQ
1970 Chevy Chevelle
545
Peak RWHP
570
Peak RWTQ
5200
Peak RPM

Engine Dyno Sheet

HP & Torque vs RPM

Power and Torque · As Tested by ATK Performance
HP Torque (ft-lb)
ATK Performance · HP451P · Measured at the flywheel · SAE Corrected · Open original sheet →
Published with the owner's permission. Dyno data shown with customer consent.

The Build

Engine
Engine ATK Performance HP451P — 454 ci Chevy big block crate, 525 HP rated
Displacement 454 ci (7.4L)
Architecture GM Big Block Chevy, 1-piece rear main seal
Induction Holley Sniper EFI — self-tuning fuel injection
Hood Cowl-induction (factory-style ram-air)
Tune Holley in-house
Drivetrain
Transmission TREMEC TKX 5-speed manual
Differential Ford 9" rear end
Driveshaft Custom
Suspension & Brakes
Front Suspension OEM (period-correct ride)
Rear Suspension OEM (period-correct ride)
Brakes 4-wheel disc conversion
Interior & Comfort
Center Console Custom — fabricated to fit
Power Windows Modern conversion
Displacement
7.4L V8 (454 ci)
Induction
Naturally Aspirated EFI
Fuel
Pump gas
Transmission
TREMEC TKX 5-spd

The Story

Of all four cars in Jim Schafer's lineup with us, the 1970 Chevelle is the traditionalist. No LS swap, no coilovers, no modern bones — just 454 cubic inches of ATK Performance HP451P big block sitting where Chevrolet would have put one in '70, breathing through a cowl-induction hood like the day it left the factory.

What's different is the brain. The big block runs Holley Sniper EFI instead of a carb — same look from the outside, but cold starts, smooth idle, and altitude compensation come standard now. ATK's own flywheel test on this motor showed 545 HP cresting at 5,200 RPM with a wide 570 ft-lb torque shelf holding from 4,200 to 4,800. The chart speaks for itself.

A TREMEC TKX 5-speed handles the shifts — same gearbox we put in the 1968 Camaro and the 1972 Chevelle, because once you've driven one you don't want anything else in a classic. Power lands at a Ford 9-inch rear, the standard for big-power muscle. Suspension stays OEM front and rear for that classic Chevelle ride, but 4-wheel disc brakes replace the original drums — Jim wanted to enjoy the car, not white-knuckle every stop.

Inside, a custom center console was fabricated to house the modern shifter, switches, and a cleaner dash layout. Power windows round out the convenience. The car looks 1970 from any angle, drives like 2025 from behind the wheel.

Built for Jim S. · Pensacola, FL

Photos

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