DCI Pontiac 400 Stroked to 455 Crate Engine

DCI 400-455 is DCI’s most popular crate engine. Featuring a Pontiac 400 cubic inch block stroked to 455 cubic inches, this authentic Pontiac stroker is perfect for street and strip use. The 400-455 is pump gas friendly for the mild daily driver. Based on production block and heads, this combination provides plenty of power with quality bottom end components to allow for endless upgrades.


The DCI 400-455 is used as the foundation for most custom built DCI engines. Please see upgrades section for a list of possibilities.

  • Engine Displacement: 455 ci
  • Horsepower: 550
  • Torque: 575 lb-ft
  • Bore/Stroke: 4.155/4.21
  • Block/Crank Combo: Pontiac 400 block, Eagle cast crankshaft
  • Bore/Stroke Ratio:  .98:1
  • Rod/Stroke Ratio: 1.57:1

The DCI 400-455 is capable of mid-11 second quarter mile times (3.55 gears and 3,200 rpm stall converter recommended for 3,500 pound car).

BlockFactory Pontiac 400 two-bolt main
PreparationHot-tanked, magged for cracks, bored and
honed with deck plates, deburred, new cam bearings,
new brass freeze plugs, checked and
cleaned for assembly
Deck HeightStock, 10.225"
CrankEagle cast stroker crank 3" mains,
2.25" rod journals
Crank PreparationCleaned, inspected, checked for
bearing clearances and journals out of round,
micro-polished, and balanced
BalancerFactory GM, two-piece cast-iron
RodsEagle 4340 H-beam, 6.625"
Rod PreparationCleaned, big and small ends
checked and fitted if needed
BearingsSpeed Pro 3/4-groove mains, Clevite 77 rod,
Clevite cam bearings
Bearing PreparationCleaned and inspected, checked for clearance
PistonsSpeed Pro Forged
Piston PreparationPin-fitted, deburred, weight-matched and cleaned
Piston to Deck Height0.010"
Piston PinsSpeed Pro, pressed or floating
with double locks
RingsSpeed Pro file-fit
Ring PreparationFitted to each individual bore,
deburred, and cleaned
Rod Bolts/Head BoltsARP, GM main and head bolts
Balancing SpecsBalanced to within half a gram
Oiling SystemModified Factory
Windage TrayNone (they shred and
come apart from rapid engine acceleration)
Crank ScraperNone
Oil PanGM stock replacement
Oil PumpMelling high-volume 60 psi (disassembled, checked for clearance andcorrected if needed, deburred, cleaned and reassembled)
Heads6X-8 '75 to '78
Head ModsHot-tanked, blasted, magged for cracks,
new guides if needed, exhaust seats opened up for
1.77-in valve, ported for application, competition valve
job, bolt holes tapped, machined for positive
oil seals, cleaned and flow-tested
Combustion Chamber Volume96-98cc
Intake Flow245-260 cfm at 0.55"
Exhaust Flow215-225 cfm at 0.55"
Compression Ratio9.25:1-9.5:1
ValvesDCI severe-duty one-piece stainless
steel, 2.11/1.77
Valve Angles35-45-60 degree
RetainersComp Cams 10-deg
KeepersComp Cams 10-deg
Valve Guidesk-liner
Valve SeatsBest Gasket Viton positive
Rocker StudsARP 7/16"
Rocker ArmsComp Cams roller tip, 1.65:1
PushrodsComp Cams chromoly 0.080", 5/16" x 9.300"
CamHydraulic flat tappet, custom ground to
DCI specs by Comp Cam
Duration at 0.050246/254
Centerline108 degrees
LSA108 degrees
Installed Position106 degrees
LiftersComp Cams hydraulic
Valve SpringsComp Cams, dual
Seat Pressure135 lb
Open Pressure320 lb
Timing ChainComp Cams double-roller
IntakeEdelbrock Performer RPM dual-plane (port-matched to heads)
Carburetor (not included)Quick Fuel or Holley HP recommended
Carburetor Size950 cfm
Carburetor ModsIdle circuit re-calibrated for application,
re-jetted for application as needed
Carburetor JetsApplication specific
Fuel Pump (not included)Holley electric 150 gph, Holley regulator, fuel line size 1/2" recommended
Distributor (not included)GM HEI or MSD billet, MSD 6AL,MSD Blaster, Taylor 8mm recommended
Total Timing32 degrees
Initial Timing20 degrees
Mechanical Advance12 degrees
Vacuum AdvanceNone
Headers (not included)Hooker, Hedman, Doug's, or Flowtech, 1.75", 32 to 36" long, 3" diameter collectors recommended

Contact DCI Motorsporst to discuss your next Engine build

Call 330-628-3354

Upgrade Options

There are too many upgrade options to list. Anything you can imagine can be upgraded, from valve covers to advanced options such as  fuel injection, turbos, and super chargers. Please contact us to discuss your next Pontiac engine.

One of our popular upgrade packages

  • Heads: Edelbrock RPM (ported to 340 cfm with 2.19″ intake valves)
  • Intake: Edelbrock Victor
  • Cam: hydraulic roller cam 254 int and 260 exh duration @ .050
  • Lifters and Rockers: solid roller, Harland Sharp 1.65 roller rockers
  • Compression Ratio: 10.75:1
  • Horsepower: 650
  • Torque: 670 lb-ft


Warranty: There is no warranty or guarantee on high performance street or race engines or parts. There is no guarantee on horsepower and torque. All horse power and torque are estimates only and can vary with fuel, altitude, improper installation, improper use, and other restrictions outside of DCI’s control.