Carburetor
The bolt-on Rocker arms and new intake in place, we replaced the Chevelle's original Quadrajet mixer with a 525-cfm Road Demon vacuum secondary carb (64/78 jets). $357
The mule
The '70 Chevelle now fitted with the Lunati rocker arms and Edelbrock intake manifold. Power measured at the rear wheels.
Our take
This was a tough one--Demon recommends its carbs for modified engines, not a factory cammed, low-compression stocker like we flogged here. Although peak gains were minimal, average power was improved through the powerband. This carb also gives us a good, easily tunable foundation to work with as more extensive modifications are made to this engine.
Before
Max torque: 278 lb-ft @ 3,800 rpm
Max power: 211 hp @ 4,100 rpm
Average torque: 267 lb-ft
Average power: 189 hp
| After
Max torque: 282 lb-ft @ 3,400 rpm
Max power: 212 hp @ 4,100 rpm
Average torque: 272 lb-ft
Average power: 192 hp | Difference
+ 4 lb-ft
+ 1 hp
|
Headers
The bolt-on
Doug's Headers with 15/8-inch primary tubes and 3-inch collectors. $530
The mule
The '70 Chevelle now fitted with the Lunati rocker arms, Edelbrock intake manifold, and Road Demon carb. Power measured at the rear wheels.
Our take
Our intake/carb combo got more air/fuel mixture flowing into the old Chevelle; the new headers evacuate the burnt gases much more efficiently than the factory cast-iron pieces. Another jump in power was the result.
Before
Max torque: 282 lb-ft @ 3,500 rpm
Max power: 212 hp @ 4,100 rpm
Average torque: 272 lb-ft
Average power: 192 hp
| After
Max torque: 295 lb-ft @ 3,400 rpm
Max power: 223 hp @ 4,100 rpm
Average torque: 286 lb-ft
Average power: 203 hp
| Difference
+ 13 lb-ft
+ 11 hp
|