Pontiac 400 Engine Build - Pump Gas Pounder
Everyone wants to build a better mousetrap. Some like to compete in the high-compression horsepower chase and some look to push the boundaries of the pump-gas combo. For this story, Tin Indian Performance (TIP) and Kauffman Racing Equipment (KRE) set out to do the latter using a factory Pontiac block, KRE's D-port heads, and various new products introduced by both companies. Ultimately, the engine is destined for TIP's Kevin Swaney's 3,500-pound race car, in which he's intent on running mid-10s.
The major components of the build up include a '67 GTO 400 block previously freshened up by Kevin. It was punched 0.035-over and stuffed with a 4.210-inch stroke crank. Aluminum rods will keep reciprocating weight down, a stout Comp roller cam will provide big duration and lift numbers to draw a copious amount of atmosphere through the KRE D-ports via a Holley 1050 Dominator and Victor intake. MSD components will light it off and combustion remains will be expelled via Hedman 1.75-inch Hedders.
KRE's aluminum D-ports are available in three different chamber sizes-65, 74, and 85 cc-and are CNC-ported to flow 310, 325, or 340 cfm. They also accept existing D-port headers and all stock Pontiac engine parts. For this engine, TIP will use the 74cc 340-cfm versions to keep compression pump-gas friendly at 11.4:1 while still providing enough airflow to produce 600-plus hp.
Follow the photos and captions to learn more and check the Engine Buildup Worksheet for further details. Then we'll see how the engine performs on the dyno. Will this two-bolt main 400 block fitted with go-fast goodies make 600-plus hp on the dyno on 93-octane and live to tell the tale? Read on.
Engine Buildup WorksheetEngine Displacement463Horsepower650Torque596 lb-ftBore/Stroke4.185/4.21-inBlock/Crank Combo400 block, bored 0.035-in/stock 4.210, stroke 455 crankBore/Stroke Ratio0.99406:1Rod/Stroke Ratio1.57:1
Bottom EndBlock Description'67 400 PreparationClean and mag, fill to water jackets with hardblock,
bore and finish-hone to size using a torque
plate, wash and assembleDeck Height10.235-inCrank455 turned down to 3-in mainsPreparationBalance rotating assemblyBalancerProfessional Products SFI-approvedRodsBME aluminum, 6.625-in, 0.020-in side clearance BearingsFederal Mogul, main clearance 0.0025-in, rod clearance 0.003-inPreparationOil feed holes opened upPistonsSRP 4.185-in forged, 0.005 piston-to-wall clearancePiston to Deck Height0.005-inPiston PinsSRP with spiral locksRingsTotal Seal 1/16-, 1/16-, 3/16-in, Moly top, cast iron secondPreparationFiled-to-fit, 0.018-in gapsRod BoltsARP 2000Head StudsARPMain StudsARP
Oiling SystemWindage TrayNoneCrank ScraperTin Indian PerformanceOil PanMorosoOil PumpMelling M54dsPreparationSpring shimmed to increase pressure
HeadsBrand340-cfm, 74cc KRE aluminum D-portsChamberHeart-shaped, fast-burnHead ModsGasket match to TIP-120240 intake gasket,
CNC-ported to 340-cfmCombustion Chamber Volume74 cc'sMaximum Flow at 28 Inches of WaterIntake341-cfm at 0.700 liftExhaust261-cfm at 0.700 liftCompression Ratio11.41:1ValvesFerrea SS 6000 series, 2.19/1.66-inRetainersComp Cams 10-degKeepersComp Cams 10-degValve GuidesBronzeValve SealsPCRocker StudsARPRocker ArmsScorpion 1.6-ratio full rollerPushrodsComp Cams, 5/16-in, 9.450-in long
CamBrandComp Cams custom-grind solid rollerDuration at 0.050265/272-degLift0.691/0.691-inCenterline110-degLobe Separation Angle110-degInstalled Position+4-degLifters BrandCrower rollerValvespringsComp CamsSeat/Open Pressure230/620-bsTiming ChainRollmaster double-roller
InductionCarb1050 Holley DominatorJetsNo. 97 squareIntake ManifoldEdelbrock Victor 850 base with tapered spacerModsPorts matched to heads
IgnitionDistributorMSD Pro-BilletAmplifierMSD 6ALCoil BrandMSD blasterWiresTaylor 8mmSpark PlugsNKG No. 8Total Timing31.5-deg advance locked out
ExhaustHeaders1.75-in HedmanCollector Size3-in
Baseline numbers were established on KRE's Superflow 901 engine dyno. Horsepower checked in at 614 at 6,200 rpm on the first pull. Torque was 563 at 4,600 rpm. Not a bad start. Baseline tuning consisted of No. 97 jets square, 28-degrees timing, and 0.020/0.020-inch valve lash.
Best Dyno PullRPMCorrected
Torque Lb-FtCorrected
HPBSFC4,300564.7462.30.4464,400572.8479.90.4304,500578.3 495.50.4224,600588.1515.00.4104,700582.9521.60.407 4,800582.0531.90.4074,900596.5556.50.4045,000573.8 546.30.4125,100576.3559.60.4155,200584.5578.70.402 5,300580.5585.80.4035,400571.2587.30.4185,500568.3 595.10.4225,600582.4621.00.4155,700574.1623.10.440 5,800564.9623.80.4245,900554.7623.10.4406,000555.0 634.10.4276,100548.0636.40.4476,200545.0643.40.445 6,300542.2650.40.4376,400527.7643.00.4396,500501.3 620.40.468
Over the course of 13 dyno pulls, Kevin and Jeff did the usual tuning with jets, valve lash, and timing. In the end, No. 97 jets square, 0.030/0.020 valve lash, and 31.5 degrees timing produced 650.4 hp at 6,300 and 596 lb-ft of torque at 4,900 rpm. We learned during tuning that advancing the timing past 32 degrees had a detrimental effect on power and the heads made peak power with 31.5 degrees of total timing. More power may be possible with more tuning, but dyno time was at a premium. Nevertheless, the mission was accomplished.

Photo Gallery: Pontiac 400 Engine Build - Pump Gas Pounder - High Performance Pontiac Magazine

Read More | Digg It | Add to del.icio.us