More Manifold & Cam

…even this small stick has its big-boy pants on, taking our mild 454 combo up to 570 hp at 5,800 rpm…

Our intermediate cam was clearly favoring the upper end of the rpm range, and at this level of cam duration a single-plane intake manifold would likely further complement the high-rpm power. To explore the effects of a change in manifold configuration, we swapped the intake to Edelbrock’s Victor Jr. 454-O, a single-plane designed for the oval-port heads. With no other changes to our test engine, the swap resulted in a classic example of a single-plane versus dual-plane comparison. Up top, we now recorded 609 hp from 6,000-6,200 rpm. With handily over 600 hp on tap, we definitely gained in bragging rights, but it came with a clear loss in torque at lower rpm. The point at which peak torque occurred moved up and moved peak torque rpm up by a surprising 900 rpm. The single-plane runner layout also resulted in a small penalty in idle vacuum, now recorded at 11.7 in-hg at 1,000 rpm.

Our final test configuration featured another large move up in camshaft specs, this time to 248/256 degrees duration at .050- and .630-inch lift, retaining the single-plane manifold from our previous test. Our big cam definitely made itself known with a raucous lope and just 7.0 in-hg of vacuum at 1,000 rpm. Following the pattern of our previous tests, the big stick once again traded torque downstairs for horsepower at the upper reaches of the tach. We now had an impressive 630 hp on tap at 6,400 rpm, with the combination pulling cleanly to a maximum of 6,700 rpm. Those numbers are pretty imposing for a pump-gas street 454!

The penalty here, as you might expect, is more torque skinned off the lower rpm range. Compared to our baseline combo we were down over 80 lb-ft at 3,000 rpm, although looking at torque from peak to peak the difference shrinks to just 10 lb-ft. As had been the case through each of our changes, the powerband moved up, trading bottom end output and idle quality for more all-out power. These compromises are the essence of what performance enthusiasts are faced with when making their camshaft decision. Our baseline cam delivered mountains of low-end grunt, and has the legs for excellent power up top. The ferocious idle of our big cam would definitely come with compromises in street driveability, but might just offer the boulevard presence and power curve you are after. With a serious converter and street tires, the torque lost down low would likely never even make itself known. When it comes to cams, one size doesn’t fit all, the right cam is tailored to your application and goals.


On The Dyno
Crane Hydraulic Roller Cams
454ci Big-Block Chevy

TQ: HP:
RPM: 222DP 234DP 234SP 248SP 222DP 234DP 234SP 248SP
3,000 539 508 487 457 308 290 278 261
3,100 539 508 487 457 318 300 287 270
3,200 542 513 491 462 330 313 299 282
3,300 549 523 501 474 345 329 315 298
3,400 558 535 512 488 361 347 332 316
3,500 567 547 521 500 378 365 347 333
3,600 575 557 528 508 394 382 362 348
3,700 581 564 533 516 409 397 376 363
3,800 585 569 539 524 423 412 390 379
3,900 587 573 543 532 436 426 403 395
4,000 587 576 547 538 447 439 416 410
4,100 587 578 552 545 458 452 431 426
4,200 585 580 558 554 468 464 446 443
4,300 583 580 563 564 477 475 461 461
4,400 580 579 567 570 485 485 475 478
4,500 576 577 569 574 493 495 488 492
4,600 572 575 571 576 501 504 500 505
4,700 567 572 572 577 508 512 512 516
4,800 563 570 574 577 515 521 524 528
4,900 559 568 574 577 522 529 536 538
5,000 555 565 575 577 528 538 547 549
5,100 552 563 575 577 536 546 558 560
5,200 549 559 574 577 543 554 568 572
5,300 545 556 572 577 550 561 578 582
5,400 541 552 569 576 556 567 586 592
5,500 536 548 566 573 561 574 592 600
5,600 530 544 561 569 566 581 598 607
5,700 524 541 555 565 569 587 602 613
5,800 516 537 549 559 570 593 606 617
5,900 507 531 542 552 569 597 608 620
6,000 497 524 534 546 568 598 609 624
6,100 485 516 524 538 563 599 609 625
6,200 470 505 516 530 555 597 609 626
6,300 524 628
6,400 517 630
6,500 509 629
6,600 500 628
6,700 491 627


By The Numbers
Crane Cam Specifications

Crane grind number: Duration at .004 inch: Duration at .050 inch: Lift: LSA:
HR 222/239-2S-10 284/292 degrees 222/230 degrees 0.576/0.598 inch 110 degrees
ZHR-296-2S-12 296/304 degrees 234/242 degrees 0.610/0.632 inch 112 degrees
HR-248/372-2S-10 310/318 degrees 248/256 degrees 0.632/0.632 inch 110 degrees


See More Online

We captured our three-cam, two-intake dyno test on video, so if you want more, log on to our Video page at PopularHotRodding.com!


SOURCE
Holley Performance Products
1801 Russellville Rd.
Bowling Green
KY  42101
270-781-9741
www.holley.com
MSD Performance
1350 Pullman Dr., Dock #14
El Paso
TX  79936
915-857-5200
www.msdignition.com
Crane Cams
1830 Holsonback Drive
Daytona Beach
FL  32117
866-388-5120
www.cranecams.com/
Air Flow Research
28611 W. Industry Drive
Valencia
CA  91355
661-257-8124
www.airflowresearch.com
Edelbrock
2700 California St
Torrance
CA  90503
310-781-2222
www.edelbrock.com