Moparts Tech Archive
Big Block
still the default 500 HP street/strip combo
fast68plymouth
just a few dyno numbers for you guys looking to build a reliable street/strip 440 based combo. its the same stuff everyone has used for years, and it still gets the job done.the engine build up is:
9.9cr, forged pistons
ported 346's with 2.14/1.81
stamped HD rockers with adj. pushrods
torker II
850 holley(900 cfm)
big headers
old DC292 cam(new MP one is better)
deep pan w/ hemi pick up
decked, squared, balanced, rod bolts, etc.
electronic dist, 17 initial, 36 total
here are the numbers:
rpm.....tq/hp
4000...456/347
4100...478/372
4200...499/399
4300...506/414
4400...512/429
4500...510/437
4600...510/447
4700...508/454
4800...508/464
4900...505/471
5000...497/473
5100...497/482
5200...489/484
5300...483/488
5400...480/494
5500...474/497
5600...466/497
5700...457/496
5800...450/497
5900...448/503
6000...439/502
6100...432/501
6200...421/497
6300...410/492
the right street/strip solid cam would be worth about 25hp, and the roller i was running (.650 lift)was worth 60hp+.
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Fast68 is right, it is the "default", no-nonsense way to reliable 500hp!!! Once you get it dialed in and your ready for more fun, toss on a cheater or big shot NOS plate and really fly!! Back the timing off to 30-32,throw in 104-110 octane, and hope the rest of the drivetrain(and you) are ready to go a second quicker in the 1/4!!!
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I would think you could go as high as the MP P4120661 Mech. 296 Duration - .557 Lift w/o sacrificing streetability. I have the .528 and it has a very mild idle in a 440.
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My old combination was very close to what "fast..." outlined, except I used an M1 intake, Holley "950" (don't believe it) HP carb, and a solid cam. It ran better than most people would have guessed and probably made an honest 530-540 HP. Hey, 10.97 @ 122.5 MPH capped up w/ a 3700# street car on pump gas ain't nothing to sneeze at.
From what I found, a good solid cam for that setup is the Racer Brown ST-21 254@.050",.520", 108 LSA. If your heads will work better with more lift, I'd guess the UltraDyne 255@.050", .582", 108 LSA would be a good choice. I ran 1.6 rockers w/ the ST-21, so the engine probably wouldn't have known the difference if I'd switched to the UD cam w/ 1.5 rockers.
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i'd have to check my notes to be sure, but the heads flow about 260/195@.500 lift. this was with the old DC/Racer Brown ssh44 cam which is 246@.050, whereas the new MP cam is 251@.050. if i were to get a solid cam for this motor, for street/strip use i'd be looking at something in the "moderate" ramp speed range, about 260@.050, .560-.590 lift, 108lsa(like a Comp 292XX lobe). this motor went 11.18@121+ in August @3550lbs. 4900 stall, 4.56's, 29.5X10.5 M/T slicks.
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