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Fuel Injected Small Block - Flexing A Stiff Arm

Building An EFI 406 For The Everyday Drag

By Mike Petralia

More Power
With the high torque testing out of the way, Lirones wanted to give the engine an extra boost in power but didn't want to sacrifice too much of its peak torque. They were, however, willing to move the torque peak up in the powerband, in order to make more top-end horsepower. Lirones swapped on Arizona Speed & Marine's modified Dart single-plane intake manifold with larger 36-lb-hr injectors and a 1,000-cfm four-bbl-type throttle body. Since the TPI system was controlled by the still effective, yet older ACCEL Gen VI ECU, Westech suggested that the new EFI system might be a bit more tunable using a new F.A.S.T. ECU.

With the new manifold, injectors, and throttle body bolted on and the F.A.S.T. ECU plugged in this new package was worth a huge gain in top-end power. And all that peak torque that really brought the 406 to life was not sacrificed that much. After all testing was completed, it wasn't hard for the engine's owner to choose the more powerful F.A.S.T. ECU/single-four barrel EFI system because he likes power. But we wanted to show you both systems' test results because it turned out that the TPI setup would make a killer everyday street motor.

406-CID EFI MOTOR SPECS
Bore x stroke: 4.155 x 3.75 = 406 cid
Compression: 10.4:1 JE forged pistons
Crank: Cola 4340 forging
Rods: Oliver 4340 steel 5.7-inch
Rings: Speed Pro moly
Bearings: Clevite
Oil system: Melling pump, Canton pan
Fasteners: ARP
Heads: AFR 210cc CNC
Induction: Arizona Speed & Marine EFI
ECUs tested: ACCEL and F.A.S.T.
Ignition: MSD with Champion plugs
Gaskets: Fel-Pro
Cam: COMP Cams, solid roller
  236/243 duration, .552-lift, 112 LS
Dampener: Fluidampr
406-CID EFI DYNO POWER AND TORQUE
TORQUE MONSTER
With modified TPI manifold,
ACCEL ECU, two-bbl throttle body,
and 32 lb-hr injectors
RPM TQ HP
3,000 492 281
3,200 487 297
3,400 489 317
3,600 488 334
3,800 485 351
4,000 484 368
4,200 481 385
4,400 477 399
4,600 468 410
4,800 454 415
5,000 437 416
5,200 418 414
5,400 398 410
5,600 375 399
AVG: 479 359
MAX TQ: 492 @ 3,000
MAX HP: 416 @ 5,000
By Mike Petralia
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