Centrifugal Supercharger
The bolt-on
Vortech Superchargers standard small-block carbureted kit with a V2 S-trim compressor running 5.5 pounds boost, along with a Mighty Demon 750-cfm blower carb. $3,500
The mule
A '69 Nova with a bone-stock 350 lower end, '70s-era open-chamber heads with 1.94/1.50-inch valves, an Edelbrock Performer intake, a Holley 650-cfm vacuum secondary carb, and a Turbo 350 transmission. Power measured at the rear wheels.
Our take
Even on this very tame engine, the Vortech blow-through setup increased power by almost 50 percent at the wheels; we calculate the gain at the flywheel to be right about 100 hp, which shows that even a small blower setup can produce big gains.
Before
Max torque: 222 lb-ft @ 2,300 rpm
Max power: 131 hp @ 4,100 rpm
Average torque: 165 lb-ft
Average power: 106 hp
| After
Max torque: 278 lb-ft @ 2,600 rpm
Max power: 194 hp @ 4,300 rpm
Average torque: 214 lb-ft
Average power: 150 hp
| Difference
+ 56 lb-ft
+ 63 hp
|
Big-Block Cylinder Heads
The bolt-on
Edelbrock Performer RPM 454-R aluminum cylinder heads, which have 315cc long/300cc short rectangular intake ports, 118cc open combustion chambers, and 2.19/1.88-inch valves. $1,780/pair
The mule
A 502 H.O. Chevy short-block with factory iron rectangular-port heads, 8.75:1 compression, topped with an Edelbrock Performer RPM 2-R intake and 800-cfm AVS carburetor. Power measured at the flywheel.
Our take
According to Edelbrock, the runner configuration optimizes intake and exhaust flow, especially on the short side, while the combustion chambers are designed to maximize chamber efficiency. In this case, it all adds up to nice power gains on the dyno.
Before
Max torque: 518 lb-ft @ 4,000 rpm
Max power: 452 hp @ 5,000 rpm
Average torque: 485 lb-ft
Average power: 367 hp
| After
Max torque: 550 lb-ft @ 4,000 rpm
Max power: 502 hp @ 5,500 rpm
Average torque: 517 lb-ft
Average power: 394 hp
| Difference
+ 32 lb-ft
+ 50 hp
|