Test 3 We tried even bigger headers, but power was down slightly. Components: same as Test 1 but with TTI 1 7/8-inch headers. RPM HP LB-FT 3,000 254 445 3,200 273 449 3,400 291 449 3,600 318 464 3,800 350 483 4,000 380 499 4,200 406 508 4,400 429 512 4,600 445 508 4,800 457 500 5,000 462 485 5,200 477 481 5,400 483 470 5,600 482 452 5,800 478 433 6,000 471 412 Note: Removing the spacer dropped power substantially-minus 30 lb-ft off peak. Test 4 We went even bigger with the manifold, and the engine liked it even less. Components: Edlebrock Super Victor intake; Holley 750 carb with 74 primary jets, 83 secondary jets; TTI 1 7/8-inch headers; 1-inch open spacer; 34 degrees total timing; 150-degree water temperature; 165-degree oil temperature. RPM HP LB-FT 3,000 238 417 3,200 255 419 3,400 269 416 3,600 285 415 3,800 311 430 4,000 341 448 4,200 369 461 4,400 395 472 4,600 421 481 4,800 442 483 5,000 455 478 5,200 471 475 5,400 479 466 5,600 480 450 5,800 474 429 6,000 469 411 Mopar specialists Hughes Engines got the nod when it came to choosing rocker arms and pushrods. You can reuse your stock rocker arms if you'd like, but the stamped rockers can deflect and become inconsistent at high rpms and high valve lift. Not all factory rocker arms are made equally, either. Though they should have a ratio of 1.5:1, it's been generally accepted that the actual ratio is closer to 1.4:1, with some measured in the 1.3 range. Hughes rockers are CNC'd aluminum, come in either 1.55:1 or 1.60:1 ratios, and have improved oiling paths through the rocker.Mopar specialists Hughes Engines got the nod when it came to choosing rocker arms and push Proper geometry is essential for all pushrod engines, but especially so for small-block Mopars. The lifter bores are at 59 degrees to the cam centerline, rather than 48 like small-block Chevys, so the lifters, pushrods, and rocker arm adjuster studs don't all align neatly.Proper geometry is essential for all pushrod engines, but especially so for small-block Mo Using the wrong length pushrods can cause the rockers to contact the valve stem incorrectly. Hughes recommends using custom pushrods with its rocker arms, and the kit includes adjustable lifter and pushrod checking tools to measure the proper pushrod length. Hafliger installed the tools as you would a regular lifter and pushrod.Using the wrong length pushrods can cause the rockers to contact the valve stem incorrectl « | 1 | 2 | 3 | 4 | 5 | » | View Full Article By John McGann Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
