383 Chevy Engine - The Ultimate 'Stick

Dyno-Thrashing 6 Camshafts In A Small-Block 383

Scott Crouse Jan 19, 2007 0 Comment(s)

Lock the garage door and break out the droplight, as this month's dyno test is all about choosing the perfectcamshaft for a 383ci stroker small-block. While the 350 may be the most popular, and the 400 more robust, the 383ci engine is still, by far, the most popular street combination. And for our testing purposes, it would unequivocally deliver robust power across a wide range of camshafts, from mild to wild.

To get the job done we paired up the technical staff of Comp Cams with the guys from SA Engine Design to perform a back-to-back test of six individual camshafts. Cylinder heads of choice were 190cc Trick Flows, and we ran three separate groups of progressively bigger camshaft profiles, pairing dual-pattern grinds against single-pattern grinds. The camshafts were run with a dual-plane Edelbrock Air Gap intake manifold, a 750-cfm Speed Demon carburetor, and set of 131/44-inch Hedman headers. Each of the tests found maximum power with 34 degrees of total spark timing with an out-of-the-box Demon carburetor. Some street tuning was performed to increase idle vacuum, but overall each package delivered a useful power curve for any given audience. To provide total coverage of each camshaft and its mannerisms we also measured the cranking compression and idle vacuum.

Check out the details and compare our dyno numbers carefully. High-rpm power may accelerate a dedicated strip machine to the fastest speed, but a hefty torque curve will definitely lay the stoplight smackdown on a race engine every time.

Engine Specs
* 383ci small-block
* 4.030-inch bore
* 3.75-inch stroke
* 11.5:1 compression
* Comp Cams valvetrain
* Milodon oil pan w/windage tray
* 91-octane pump gas
* 160-degrees water temperature
* ARP engine bolts
* Fel-Pro gasket set
* 190cc Trick Flow cylinder heads
* 750-cfm Speed Demon
* Edelbrock intake
* Hedman headers
* Champion spark plugs
* Lucas oil 5W30
* MSD Distributor, wires, ignition

0607ch_04_z 383_chevy_engine 4/5










Dual-Pattern

Group #1  
PN 12-408-8
Grind XR258HR-10
Intake valve lift 0.480 inch
Exhaust valve lift 0.487 inch
Intake duration at 0.050-inch lift 206 degrees
Exhaust duration at 0.050-inch lift 212 degrees
LSA 110
Intake valve opening 23
Intake valve closing 55
Exhaust valve opening 66
Exhaust valve closing 18
Cranking compression 220 psi
Idle vacuum at 900 rpm 17 inches
Peak torque 483
Peak horsepower 416
Average torque at 2,500-5,500 rpm 456
Average horspower at 2,500-5,500 rpm 345
RPM TQ HP
2,500 440 209
3,000 457 261
3,500 480 320
3,800 483 350
4,000 482 367
4,500 471 404
5,000 437 416
5,500 390 408
6,000 N/A N/A
6,300 N/A N/A

0607ch_05_z 383_chevy_engine 5/5

Comp Cams offers more lobe profiles than just about any other camshaft manufacture today. We dreamed the dream and Comp supplied it: the perfect 383ci camshaft.










Single-Pattern

Group #1
PN NA
Grind 3311S/3311SHR110
Intake valve lift 0.480 inch
Exhaust valve lift 0.480 inch
Intake duration at 0.050-inch lift 206 degrees
Exhaust duration at 0.050-inch lift 206 degrees
LSA 110
Intake valve opening -3
Intake valve closing 29
Exhaust valve opening 37
Exhaust valve closing -11
Cranking compression 220 psi
Idle vacuum at 900 rpm 16.5 inches
Peak torque 495
Peak horsepower 442
Average torque at 2,500-5,700 rpm 466
Average horsepower at 2,500-5,700 rpm 362
RPM TQ HP
2,500 447 213
3,000 462 264
3,500 493 328
3,700 495 348
4,000 492 375
4,500 484 415
5,000 460 438
5,300 438 442
5,500 420 440
5,700 402 437

Final Verdict
Big cams make high-rpm power-but at the expense of low idle vacuum and poor street drivability. Small cams trade a bit of that high-end power but offer good street manners, while providing enough low-rpm torque to hang with even the biggest beast on the streets. In the end it all comes down to a trade-off between drivability and balls-out high-performance power.

Sources

Comp Cams
Memphis, TN 38118
800-999-0853
http://www.compcams.com
Hedman Hedders
Whittier, CA 90602
562-921-0404
www.hedman.com
Holley Performance Products
Bowling Green, KY 42101
270-781-9741
http://www.holley.com
Trick Flow Specialties (TFS)
Tallmadge, OH 44278
Barry Grant Inc.
Dahlonega, GA 30533
Fel-Pro
Westminster, CA 92683
www.fellpro-only.com
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