1969 Firebird "Little Big Chief" Chassis Dyno Test
Over the first three installments of this story, you learned that Jason Korb of Middletown, Pennsylvania, wanted to rebuild the Pontiac 350 engine in his '69 Firebird for more power and easy cruising, but he didn't want to give up driveability or break the bank to do it. He contacted RaceKrafters Automotive Machine in Lancaster, Pennsylvania, where Bob and Craig Wise scienced out a combination to suit Jason's requirements.
HPP followed the build-up from beginning to end. In Part I (June '08) we covered the machine work on the bottom end and the porting of No. 17 small-valve heads and larger intake valve swap to improve power, while avoiding the higher cost of new heads. Part II (July '08) took us through the assembly of the engine and illustrated where upgrades were made and money was saved without compromising quality. Then came engine dyno testing in Part III (Aug. '08), where the 0.030-over 350 produced 342 horsepower on RaceKrafters' in-house Stuska engine dyno.
Following the engine dyno session, Jason, a professional mechanic by trade, installed it into his beautiful '69 Firebird with the help of his son, Andrew, and wife, Ann. The value of investing in engine dyno testing proved its worth when, after tightening the final bolt, Jason turned the ignition key and the 350 jumped to life without any hesitation and nary a turn of the starter. He told HPP, "The engine started so quickly that I got scared. I expected it to at least crank over a few times." This fresh Pontiac 350 ran great and a drive around town proved that it was a sprightly performer for its small displacement.
Already equipped with 3.90:1 rear gears, after the first run on the highway, the Korb family agreed that if they wanted to use the car for the intent that it was built, either an overdrive transmission or milder gears would need to be installed. At 65 mph, the little engine was screaming, which makes for not only a high rate of wear, but poor fuel mileage as well.
The decision was made to install a 200-4R four-speed automatic transmission, along with a 2,200-rpm stall speed torque converter and a Fourth-gear-only lock-up. HPP wasn't present for the transmission swap, which Jason performed in his home garage. He stated the kit he purchased from Gear Star-which included a crossmember-fit and worked as represented.
With the engine's highway rpm now under control, HPP joined forces with the Korb family and the crew at RaceKrafters to put the final tune on the Firebird via the in-house DynoJet chassis dyno-just in time for the summer cruise season.
350 Pontiac Chassis Dyno TestDyno testing was performed using 93-octane fuel.RPMHPTorqueAir/Fuel Ratio3,400149.51230.8614.353,600189.62276.6113.893,8002 07.45286.7413.584,000219.19287.8213.344,200230.462 88.1913.204,600242.45276.7813.024,800250.71271.811 3.085,000249.10261.5513.025,200247.92250.5012.855, 400226.53220.3612.81Note: This test was performed with no air filter in place.
Once the air filter was attached, the engine picked up
slightly over 2 horsepower at peak to 252.
ConclusionIt cost $4,842 (plus $400 for dyno testing) to build this 350 that puts 342 hp to the flywheel and 252 rwhp to the ground reliably. Thanks to forward thinking on Bob Wise's part, the heads flow enough to support more cam, more carb, and more power, should Jason decide to go there in the future.
In the end, the Korb family received what they asked for. Their '69 Firebird not only looks great, it also has a potent, yet smooth, Pontiac 350 engine that should make it stand out in a sea of 400 and 455 cars at the shows and cruises. "There is a night-and-day difference between how the Bird was before and after the engine swap," explained Jason. "The power is spectacular for a 350, it launches beautifully when you ease into the throttle, or you can make it go sideways if you mash it! Since I swapped in the 200-4R, the Firebird is more highway friendly as well. Now I drive it as much as I can because it performs so well and is comfortable at highway speeds."
Let's not forget what chassis dyno tuning can do, either. This Bird made 230 rwhp when it arrived, and left making 252 rwhp after dialing in the carb to better match the drivetrain. A 22 hp increase and proper air/fuel ratio at full throttle and cruise are certainly worth the effort.
Engine Build Up WorksheetDisplacement359 ciBore/Stroke3.905/3.750-inBore/Stroke Ratio1.041:1Rod/Stroke Ratio1.77:1Bottom EndBlockStock 350 PontiacDeck Height10.210-inCrankshaftStock Pontiac 3.75-in strokeBalancerStock Pontiac replacementConnecting RodsPontiac cast 6.625-inBearingsFederal Mogul 0.10 undersizePistonsSterling cast flat-top with four valve reliefsPiston PinsSterling, press-fitPiston RingsSpeed-Pro moly facedEnd Gap0.017-inch top, 0.015-inch secondPiston to Deck Height-0-Rod BoltsARPOiling SystemOil PanMilodon wet-sumpOil PumpMelling high-volumeWindage TrayPontiacHeadsCasting No.17Combustion Chamber Volume80 ccFlow at 28 Inches of Depression224/196-cfm at 0.600 liftValves2.02/1.66-in Manley SSCompression Ratio9.01:1RetainersComp Cams chrome-molyRocker StudsARPRocker ArmsHarland Sharp 1.5:1 rollerPush RodsComp Cams 5/16 x 0.80-in wallPush Rod Length9.130-inCamBrandComp Cams flat-tappet hydraulicDuration at 0.050-in218/224-degLift0.462/0.470-inCenterline106-degLSA110-degInstalled Position106-degLiftersComp CamsValvespringsComp Cams dual designSeat Pressure117 psi at 1.600 inOpen Pressure232 psi at 1.100 inTiming ChainComp Cams rollerGasketsFel-ProInductionCarburetorEdelbrock 650-cfm, No. 1806 IntakeEdelbrock Performer RPM, dual-planeFuel Line3/8-inIgnitionDistributorMSD Pro BilletPlugsAutolite No. 86WiresMoroso ExhaustHeadersHedman 1.75-in primaries, 3-in collectorSystem2.5-in dual, Flowmaster mufflers

Photo Gallery: 1969 Firebird "Little Big Chief" Chassis Dyno Test - High Performance Pontiac Magazine

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