400 ponco street engine build



400 ponco street engine build

Postby grumpyvette » August 19th, 2009, 4:04 pm

http://www.highperformancepontiac.com/t ... index.html

Pontiac Flat Top Pistons
The 87cc combustion chambers will provide 10:1 compression when combined with the 4.181 bore, the flat-top piston's compression height and valve reliefs, 0.005 piston-to-deck height, and the volume of the head gasket. A set of 2.11/1.66-inch stainless valves is included when the assembled head is purchased.
Pontiac Exhaust Ports
"D"-shaped exhaust ports were proven decades ago on GM Tech Center dynos to work best on high-performance engines. Though the heads are based on the round-port R/A-IVs, the exhaust port design was changed in the Edelbrock head to this D-shape. Nevertheless, the round-port manifold or header configuration is required when using these heads.

Engine Buildup Worksheet
Displacement 400/462
Bore/Stroke 4.181x4.210-in
Block/Crank Combo ’67 400/4.210 stroker
Bore/Stroke Ratio 0.993:1
Rod/Stroke Ratio 1.574:1


Bottom End
Block ’67 GTO 400, code WT
Preparation Bored and honed 0.060-over
Deck Height 10.250-in
Crankshaft Joe Sherman Racing cast 455 stroker
Preparation Balanced
Balancer Aftermarket replacement, degreed
Rods Cast, 6.625-in
Preparation Size the big and little ends, install new rod bolts, balanced
Bearings King
Pistons KB Hypereutectic, 0.030-455 flat-top with valve reliefs
Piston to Deck Height 0.005-inch
Piston Pins KB press-fit
Piston Rings Hastings moly top, cast-iron second
Head Bolts ARP
Balancing Spec 2,210g bob weight


Oiling System
Oil Pan Replacement with baffle
Oil Pump Mellings


Heads
Brand Edelbrock aluminum, 60579, closed chamber
Modifications As delivered from Edelbrock
Combustion Chamber Volume 87cc
Maximum Flow at 28 Inches of Pressure:
Intake 275-cfm at 0.700
Exhaust 185-cfm at 0.700
Compression Ratio 10.0:1
Valves Edelbrock 2.110/1.660-in
Angles Used in Valve Job 30-, 45-, 60-deg
Mods None
Retainers Chromoly
Keepers Steel 7-deg
Valve Guides Edelbrock bronze
Rocker Studs ARP 7/16-in
Roller Rocker Arms PRW full roller, 1.52:1
Pushrod Diameter 5/16-in
Pontiac GTO 400 Engine Block Build Up - Poncho Honcho

Cam
Brand Comp Cams hydraulic roller
Grind XFI 280HR
Duration at 0.050 230/236-deg
Lift 0.540/0.543-in
Centerline 108-deg
Lobe Separation Angle 110-deg
Installed Position 108-deg
Lifters Comp Cams hydraulic roller
Valve Springs Comp Cams dual
Seat Pressure 145 lbs
Open Pressure 395 lbs
Timing Chain Comp Cams dual-roller


Induction
Intake Manifold Performer RPM
Mods Plenum clean-up
Carb Edelbrock No. 1412, 800-cfm
Mods None
Jets/Primary 0.113
Jets/Secondary 0.101
Primary Metering Rod Size 0.071-0.047
Fuel Line 3/8-in diameter/No. 6 AN


Ignition
Distributor Stock-type, Pertronix conversion
Coil MSD
Wires ACCEL 7mm solid core
Total Timing 40-deg
Initial Advance 16-deg
Mechanical Advance 24-deg
Vacuum Advance None


Exhaust
Brand Mad Dog Exhaust Products custom
Primary Tube Diameter 1.875-in
Primary Tube Length 30-in
Collector Size 3 1/2x7-in
Sherman explained to Middleton that this 462 cubic inch combination would produce 500-plus horsepower at a livable 5,000 to 5,200 rpm with almost 600 lb-ft of torque. Though we typically see forged rods and pistons in these types of builds, Sherman also said that the hypereutectic pistons and cast rods would be cost-effective as compared to forged pieces, and durable in this application because peak power is made at just 5,200 rpm. Middleton was floored! To his old-world brain, these power figures bordered on Amtrak diesel territory! Sherman suddenly found himself with Middleton's Pontiac engine to build as well. Let's see how it all turned out.

Dyno Results
The engine was dynoed on Joe Sherman Racing Engine's SuperFlow 901 engine dyno. For this pull, the fuel was 91-octane, the timing was set to 39 degrees and the jets were the same as listed in the engine buildup worksheet.

RPM Torque HP
3,400 582.8 377.3
3,600 587.1 402.4
3,800 590.4 427.2
4,000 592.5 451.2
4,200 590.0 471.8
4,400 582.1 487.7
4,600 570.9 500.0
4,800 554.2 506.5
5,000 531.9 506.4
5,200 508.1 506.7
5,400 479.9 493.4
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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