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 Given our high-lift cam (0.600/0.619...  Given our high-lift cam (0.600/0.619 inch), valvespring setup was crucial. Our man Brul carefully measured the new springs to ensure proper installation.  The height mic revealed that...  The height mic revealed that we had 1.870 inches of available spring room. We then had to subtract 0.060 inch for spring seats, which protect the aluminum head from the valvespring and also positively locate the spring. This left us with 1.810 inches, and Brul went with this as our installed height. Why? Subtracting 0.620 inch for our cam's exhaust lift left 1.190 inches. Coil bind happens at 1.085 inches, which left us with a near-perfect 0.105-inch clearance.  The difference between old...  The difference between old and new is striking, but they do have their similarities. Both springs specify an installed height of 1.800 inches; at this height, the old spring measured 135 pounds, while the new was 130 pounds. Open load, measured at 1.200 inches, was even closer: 320 pounds for the old, 318 for the new. Our beehive springs will run at a nominally lower rate since we used a slightly higher installed height. Our call to Powerhouse Products also yielded an E-Z Valve Lash Wrench. The Pro Magnum lifters we installed in anticipation of our high-rpm endeavors take a bit less preload than Comp's regular-duty lifters. Glory Run
The point of this exercise was to demonstrate the vastly improved valve control we achieved by switching to beehive valvesprings, as opposed to chasing peak power. Ah, who are we kidding? There was time for a glory run at the end of the day, and this is CHEVY HIGH PERFORMANCE, right? Dyno details are as before, except we bumped the timing up to 39 degrees and fattened up our Mighty Demon mixer with an 85 primary/90 secondary jet combo. Our rev-happy 406 rewarded us with 4 more horsepower and 11 extra pound-feet of torque when compared to our Jan. '07 test, made with a 750-cfm Mighty Demon, with gains shown throughout the powerband. Our old nemesis valve bounce was nowhere to be found. | RPM | LB-FT | HP | | 2,600 | 392 | 194 | | 2,700 | 396 | 204 | | 2,800 | 403 | 215 | | 2,900 | 412 | 227 | | 3,000 | 421 | 241 | | 3,100 | 435 | 257 | | 3,200 | 451 | 275 | | 3,300 | 465 | 292 | | 3,400 | 476 | 308 | | 3,500 | 484 | 323 | | 3,600 | 492 | 337 | | 3,700 | 500 | 352 | | 3,800 | 506 | 366 | | 3,900 | 511 | 379 | | 4,000 | 516 | 393 | | 4,100 | 520 | 406 | | 4,200 | 525 | 420 | | 4,300 | 530 | 434 | | 4,400 | 535 | 448 | | 4,500 | 538 | 461 | | 4,600 | 541 | 473 | | 4,700 | 542 | 485 | | 4,8,00 | 544 | 497 | | 4,900 | 544 | 508 | | 5,000 | 544 | 518 | | 5,100 | 543 | 527 | | 5,200 | 542 | 536 | | 5,300 | 540 | 544 | | 5,400 | 537 | 552 | | 5,500 | 533 | 558 | | 5,600 | 529 | 564 | | 5,700 | 524 | 569 | | 5,800 | 519 | 574 | | 5,900 | 514 | 578 | | 6,000 | 509 | 582 | | 6,100 | 503 | 584 | | 6,200 | 496 | 586 | | 6,300 | 489 | 586 | | 6,400 | 481 | 586 | | 6,500 | 473 | 586 | | 6,600 | 467 | 587 | | 6,700 | 458 | 585 | | 6,800 | 444 | 575 | | 6,900 | 430 | 565 | | 7,000 | 416 | 555 | | Average torque | 490.4 lb-ft | | Average power | 447.3 hp | | Sources | Coast High Performance
Torrance, CA
310.784.1010
coasthigh.com | Comp Cams
Memphis, TN
800.999.0853
compcams.com | Federal Mogul (Fel-Pro Gaskets)
Pontiac, MI
248.354.7700
federal-mogul.com | Powerhouse Products
Memphis, TN
800.872.7223
powerhouseproducts.com |
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