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 effi ciently 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
Carb Spacer
The Bolt On
Wilson manifolds 1-inch open carb spacer. $82
The Mule
A 10.2:1-compression 540ci big-block with a hydraulic roller cam spec'd out at 0.566/0.566 inch lift, 242/248 degrees duration, and 112 LSA hydraulic roller cam, along with AFR 335 cNc ported heads, a Performer RPm Air Gap manifold, and an 850 mighty Demon carb. Power measured at the flywheel.
Our Take
Open carb spacers increase plenum volume, which usually leads to increased mid-range and top-end power. That's the effect the spacer had on this engine, at the expense of the peak torque; on the other hand, average power was improved. According to Westech's Steve Brul, some combos like a spacer, some don't; you have to try it and see. This one liked it.
Before
Max torque: 669 lb-ft @ 4,000 rpm
Max power: 658 hp @ 6,200 rpm
Average torque: 632 lb-ft
Average power: 556 hp
After
Max torque: 663 lb-ft @ 4,000 rpm
Max power: 668 hp @ 6,200 rpm
Average torque: 635 lb-ft
Average power: 559 hp
Difference
- 6 lb-ft
+ 10 hp
Crossover Pipe
The Bolt-On
Flowmaster Scavenger crossover Pipe added into a Flowmaster Delta Force 3-inch dual exhaust system. $187
The Mule
A '67 SS camaro with a 10.5:1 compres sion 385ci stroker small-block running an Isky mechanical street roller cam, ported World Sportsman II heads, a ported edelbrock Victor Jr. intake manifold, a 750-cfm Holley Pro series carb, and a T-56 six-speed trans. Power measured at the rear wheels.
Our Take
According to our own Kevin mcclelland, "The purpose of the Flowmaster Scavenger crossover pipe is to increase the exhaust gas velocity in the large 3-inch system, providing a torque boost along with a few extra top end ponies." Looking at the numbers, that's exactly what happened.
Before
Max torque: 378 lb-ft @ 4,700 rpm
Max power: 390 hp @ 5,800 rpm
Average torque: 369 lb-ft
Average power: 354 hp
After
Max torque: 390 lb-ft @ 4,600 rpm
Max power: 395 hp @ 5,700 rpm
Average torque: 378 lb-ft
Average power: 363 hp
Difference
+ 12 lb-ft
+ 5 hp
Dyno Thrashin'
Hydraulic Roller Cam
The Bolt-On
Isky Retro Fit Hydraulic Roller camshaft and lifters, 0.485/0.505 inch lift (intake/exhaust), 217/225 degrees duration at 0.050, ground with a 108-degree LSA. $835
The Mule
A 10.5:1-compression 350 small-block with 64cc Vortec heads, an edelbrock Performer RPm intake, 650-cfm Holley carb, and an Isky hydraulic flat-tappet cam with 0.465 inch lift (intake and exhaust), 221 degrees duration at 0.050, and a 108-degree LSA. Power measured at the flywheel.
Our Take
The specs on these two cams are very similar, but the advantages of running a hydraulic roller cam-specifically the increase in area under the curve and the reduction of frictional losses-are clearly demonstrated.
Before
Max torque: 429 lb-ft @ 3,800 rpm
Max power: 376 hp @ 5,500 rpm
Average torque: 373 lb-ft
Average power: 296 hp
After
Max torque: 438 lb-ft @ 3,700 rpm
Max power: 403 hp @ 5,700 rpm
Average torque: 384 lb-ft
Average power: 349 hp
Difference
+ 9 lb-ft
+ 27 hp
Small-Block Cylinder Heads
The Bolt-On
Brodix IK 180 aluminum cylinder heads, which have 180cc intake runners, 64cc chambers, and 2.02/1.60-inch valves. $1,014/pair