Camshaft Specifications
ManufacturerComp Cams
Part Number12-678-4
TypeSolid flat-tappet
Valve lift at 0.0500.520/0.540-inch intake/exhaust
Duration at 0.050244 degrees/252 degrees intake/exhaust
Lash (cold)0.012/0.012 intake/exhaust
Lash (hot)0.016/0.016 intake/exhaust
Intake centerline106 degrees
Lobe separation110 degrees
Dyno Details
Headers 23/4 Hedman long tubes
Advance38 degrees
Fuel91-octane unleaded
725-cfm Road Demon
Max torque at rpm398 at 4,900
Max power at rpm417 at 6,500
Average torque 371
Average power379
750-cfm Mighty Demon
Max torque at rpm415 at 4,800
Max power at rpm434 at 6,600
Average torque 389
Average power397
Nitrous Works Plate175-Shot
Advance31 degrees
Max torque at rpm581 at 5,300
Max power at rpm607 at 5,700
Average torque452
Average power467
Engine Balance
Rod (rotating)449 g
Rod insert39 g
Oil allowance4 g
Piston517 g
Piston pin113 g
Locks4.5 g
Rings47 g
Rod (reciprocating)152.5 g
Total rotating984 g
Total reciprocating834 g
Total bob-weight1818 g
355ci Buildsheet
Specifications not listed are the same as stock. Except as noted, all dimensions are in inches or fractions thereof. All prices sourced through Summit Racing and JEG's.
Displacement355 ci
Bore x Stroke4.030 x 3.480
Compression 10.25:1
Rod center-to-center5.700
Piston deck height-0.012
Chamber volume64cc
Rod-bearing clearance0.0027
Crank endplay0.0060
Piston-ring endgap0.022 top; 0.024 second
Main bearing-cap torque65 lb-ft (moly-lube)
Rod-bolt torque50 lb-ft (moly-lube)
Head-bolt torque65/70 lb-ft (moly-lube)
W/DEMON 725
rpmLb-FtHP
4,000370.6282
4,100369.1288
4,200375.2300
4,300389.7319
4,400394.1330
4,500393.4337
4,600397.2348
4,700397.6356
4,800397.9364
4,900398371
5,000397.1378
5,100396.7385
5,200394.6391
5,300391395
5,400386.9398
5,500384.9403
5,600383408
5,700378.8411
5,800373.3412
5,900366.4412
6,000357.3408
6,100352.1409
6,200346.6409
6,300341.7410
6,400339.4414
6,500337417
6,600331.1416
6,700325.7415
6,800317.7411
W/DEMON 750
RPMLb-FtHP
4,000407.1310
4,100409319
4,200410.6328
4,300412.9338
4,400411.9345
4,500412.7354
4,600413.6362
4,700415371
4,800415.3380
4,900413.9386
5,000413.6394
5,100412.5401
5,200409.4405
5,300406.3410
5,400403414
5,500401420
5,600397.7424
5,700394.1428
5,800389.8430
5,900378.2425
6,000372.8426
6,100367.4427
6,200362.3428
6,300357.7429
6,400353.9431
6,500349.8433
6,600345.2434
6,700339.7433
6,800331.2429
W/Nitrous
RPMLb-FtHP
4,000384.8293
4,100385.9301
4,200397317
4,300402.4329
4,400404.8339
4,500407.8349
4,600410.1359
4,700408.3365
4,800409.3374
4,900409.4382
5,000409.7390
5,100409.8398
5,200416.8413
5,300580.6586
5,400576.3593
5,500573.1600
5,600568.8606
5,700558.9607
5,800547.6605
5,900532.9599
6,000523.5598
6,100516.3600
6,200510.6603
6,300503.7604
6,400494.9603
6,500355.1439
6,600346.5435
6,700335.3428
6,800325.2421