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MSD Ignition Box - PT. 24: Spark Box

Computerized Timing Is Here To Stay

By Mike Petralia

It Gets Even Weirder
Since peak numbers are only a small part of the power making game, we've grown accustomed to analyzing average power gains to determine if a change was worth the effort. Well, this month's test averages perplexed us as well. Even though power was up at the low end, the drop at the top made average gains net zero! At least in the torque department. Average horsepower actually fell off by 3, which really sucked, considering how hopeful were going into this test. One positive note about this month's test was that in a car, the motor would have pulled harder off the line this month than it did last month. But we'd have to short-shift it and that's not really an advantage to in our book.

Dyno Testing Part 24Instead of comparing this month's test, Number 40, to the last test from last month as we usually do, we're comparing it to the second test from last month, Number 37. That's because in that test we were running locked-out ignition at 38 degrees and 91-octane gas. This is the combination that was detonating and losing the most low-end power, so it was the one we wanted to compare to. Ironically, this month, in test Number 40 DM did not detonate, even though the engine set-up was exactly the same. The two exceptions this month were fuel from a different source and testing done at a different facility.

Danger Mouse specs for Part 23-Test 37*

*Previous test from last month: 355 cid, 12.5:1 cr, 4.030-bore 4-bolt Motown block, 3.48-stroke Lunati crank, 5.7-inch Lunati rods, Lunati flat-top forged pistons, Total Seal ductile iron Gapless top rings, Edelbrock Victor Jr. heads (64cc chambers, 215cc runners, 2.08" intake valves, 1.60" exhaust valves), Edelbrock Super Victor intake manifold, COMP Cams XR286R solid roller camshaft installed @ 105 intake CL (248/254 @ .050, 286/292 adv, .606/.612 lift w/ COMP 1.6:1 rockers, 110 LS), Carb Shop modified Holley HP950, 38 degrees locked-out ignition advance, 91-octane

Danger Mouse specs for Part 24-Test 40:

Same as above but with 35 degrees ignition advance starting at 2,400 rpm, ramping up to 38 total at 5,500 rpm, 91-octane

We're always looking for new ideas. Do you have a better one for Danger Mouse? Send your test suggestions to:

Super Chevy MagazineAttn: Danger Mouse
720 Hundley Way
Placentia, CA 92870
Or e-mail: terry.cole@primedia.com

Test 37* Test 40 T37 vs. T40
RPM TQ HP TQ HP TQ HP
2600 371 184 361 179 -10 -5
2800 365 194 383 204 +18 +10
3000 378 216 392 224 +14 +8
3200 388 236 401 245 +13 +9
3400 388 251 406 263 +18 +12
3600 391 268 407 279 +16 +11
3800 404 293 414 300 +10 +7
4000 414 315 427 326 +13 +11
4200 422 338 437 350 +15 +12
4400 426 357 439 368 +13 +11
4600 439 385 444 389 +4 +4
4800 453 414 453 414 0 0
5000 463 441 458 436 -5 -5
5200 466 461 458 453 -8 -8
5400 467 480 457 470 -10 -10
5600 464 495 454 484 -10 -11
5800 460 508 448 495 -12 -13
6000 456 521 444 507 -12 -14
6200 453 534 440 520 -13 -14
6400 447 544 433 528 -14 -16
6600 435 547 423 532 -12 -15
6800 425 550 411 532 -14 -18
7000 414 552 392 523 -22 -29
Max 467 552 458 533
Avg 426 395 425 392 0 -3
By Mike Petralia
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