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474ci Engine Build - Pump-Gas Poncho Power
Engine Buildup Worksheet
Engine
Engine Displacement 473.5 ci
Peak Horsepower 578 at 5,500 rpm
Peak Torque 588 lb-ft at 4,700 rpm
Bore/Stroke 4.212x4.25-in
Bore/Stroke Ratio 0.991:1
Rod/Stroke Ratio 1.60:1
Bottom End
Block Description YC-code No. 485428
Year ’71
Block Preparation Bored 0.060-in
Deck Height Zero
Crankshaft Butler Performance, forged-steel, 4.25-in stroke, 3.25-in main journal, 2.20-in rod journal
Crank Preparation Normal
Main Caps Pro-Gram Engineering, No. PRO-P455F front, No. PRO-P455C center three, No. PRO-P455R rear
Main Bearing Clearance 0.003 in
Balancer Performance Street Balancer No. PBO-PB1056ST
Rods Eagle Specialty Products, forged-steel, H-beam, 6.800-in length, 7/16-in ARP bolts
Bearings Federal Mogul No. 151M-STD main journal, Federal Mogul 8-7200CH-STD rod journal
Piston Ross custom, forged-aluminum, 4.211-in diameter, flat-top, 439.5 grams, 8.5cc reliefs
Piston to Deck Height Zero
Piston Pins Ferrea No. P70028-8, forged-alloy, 0.990-in diameter, 138 grams
Piston Rings Total Seal No. CR3455-65, plasma-moly, file-fit, 0.018-in gap
Fasteners ARP 194-5601 four-bolt main-stud kit
Balanced Yes
Oiling System
Windage Tray No
Crank Scraper No
Oil Pan Canton No. 15-450, road-race
Oil Pump Melling M54F
Oil Shell Rotella 30W
Heads
Casting Number Edelbrock No. 60569-2
Chamber Open, hand-smoothed
Combustion Chamber Volume 90 cc’s
Compression Ratio 9.95:1
Head Mods Fully ported intake and exhaust ports
Intake Port Volume Approx. 220 cc’s
Intake/Exhaust Flow Ratio 75 percent
Intake/Exhaust Flow at 28-in:
0.200 140/86 cfm
0.300 201/173 cfm
0.400 258/199 cfm
0.500 292/217 cfm
0.600 312/230 cfm
0.700 316/236 cfm
Intake Valve Ferrea No. 5073, stainless steel, 2.11-in, 5.100-in length
Exhaust Valve Ferrea No. 5144, stainless steel, 1.77-in, 5.100-in length
Angles Multi-angle with 45-deg seats
Retainers Comp Cams No. 740-16, 10 deg
Locks Comp Cams No. 611-16, 10 deg
Valvesprings Lunati No. 73100-16
Install Height 1.79 in
Seat Pressure 137 psi
Open Pressure 338 psi
Valveguides Bronze, 0.530-in diameter
Valve Seals Viton
Rocker Studs ARP No. 100-7101, 7/16-in
Rocker Arms Comp Cams No. 19060, full roller
Rocker Ratio 1.5:1
Pushrods Butler Performance No. SBR-581-R-16, 5/16-in diameter, 8.80-in length, chrome-moly
Fasteners ARP No. 190-3605 head-bolt kit
474ci Engine Build - Pump-Gas Poncho Power
Cam
Brand Comp Cams custom Butler grind
Type Hydraulic roller
Duration at 0.050 242/248-deg
Lift 0.540/0.562-in with 1.5:1 rockers
Intake Centerline Installed at 106.5 deg
Lobe Separation Angle 110 deg
Lifters Comp Cams No. 857-16
Timing Set Butler Performance No. JPP-5614LB-5, 0.005-in undersized, nine-way adjustable
Timing Chain Type Billet-steel roller
Distributor Driven Gear BOP No. PDG38, polymer, for MSD distributor
Induction
Carb Barry Grant Demon
Size 850 cfm
Mods None
Jets Front/Rear No. 81/89
Fuel Pump RobbMc No. 1006
Intake Manifold Edelbrock Victor No. 2957, modified by Butler Performance
Spacer 1-in phenolic, open design
Fuel Used for Test 92-octane BP
Ignition
Distributor MSD Billet HEI
Coil MSD in-cap
Wires MSD 8mm
Total Timing 40 deg
Spark Plugs NGK No. R5671A-7, gapped at 0.050 in
Exhaust
Headers Doug’s four-tube
Primary Diameter 1.75-in
Collector 3.00-in
Gaskets
Brand No. SPM-KSX703-74, complete Pontiac overhaul
At The Dyno
Conditions
Actual Air temp 74 deg F; Baro: 28.59-in of Hg; Humidity: 45 percent
Corrected To Air temp: 60 deg F; Baro: 29.92-in of Hg; Humidity: dry
Water Temp 195-deg
Oil Temp 195-deg
Corrected Dyno Results
RPM HP Torque
3,100 315 533
3,200 326 535
3,300 336 535
3,400 343 530
3,500 352 528
3,600 361 527
3,700 372 528
3,800 385 532
3,900 411 554
4,000 434 570
4,100 446 572
4,200 459 575
4,300 478 583
4,400 489 584
4,500 497 580
4,600 513 586
4,700 527 588
4,800 535 585
4,900 547 587
5,000 554 582
5,100 561 578
5,200 566 572
5,300 574 569
5,400 575 559
5,500 578 552
5,600 571 535
5,700 572 527
Pull Log
Pull 1: 81/89 jets; 40 deg; 577 hp at 5,400 rpm; 588 lb-ft at 4,800 rpm
Pull 2: 77/85 jets; 40 deg; 567 hp at 5,400 rpm; 585 lb-ft at 4,600 rpm
Pull 3: 77/85 jets; 38 deg; 564 hp at 5,300 rpm; 582 lb-ft at 4,700 rpm
Pull 4: 75/83 jets; 38 deg; 547 hp at 5,500 rpm; 568 lb-ft at 4,800 rpm
Pull 5: 75/83 jets; 35 deg; 547 hp at 5,300 rpm; 568 lb-ft at 4,600 rpm
Pull 6: 81/89 jets; 40 deg; 570 hp at 5,500 rpm; 586 lb-ft at 4,600 rpm
Pull 7: 81/89 jets; 42 deg; 578 hp at 5,500 rpm; 588 lb-ft at 4,700 rpm
Average Horsepower/Torque from 3,200 to 5,600 rpm
Pull 1: 470/559
Pull 2: 463/550
Pull 3: 463/550
Pull 4: 451/536
heres a different build
Pull 5: 452/539
Pull 6: 468/558
Pull 7: 480/561
474ci Engine Build - Pump-Gas Poncho Power
Engine Buildup Worksheet
Engine
Engine Displacement 473.5 ci
Peak Horsepower 578 at 5,500 rpm
Peak Torque 588 lb-ft at 4,700 rpm
Bore/Stroke 4.212x4.25-in
Bore/Stroke Ratio 0.991:1
Rod/Stroke Ratio 1.60:1
Bottom End
Block Description YC-code No. 485428
Year ’71
Block Preparation Bored 0.060-in
Deck Height Zero
Crankshaft Butler Performance, forged-steel, 4.25-in stroke, 3.25-in main journal, 2.20-in rod journal
Crank Preparation Normal
Main Caps Pro-Gram Engineering, No. PRO-P455F front, No. PRO-P455C center three, No. PRO-P455R rear
Main Bearing Clearance 0.003 in
Balancer Performance Street Balancer No. PBO-PB1056ST
Rods Eagle Specialty Products, forged-steel, H-beam, 6.800-in length, 7/16-in ARP bolts
Bearings Federal Mogul No. 151M-STD main journal, Federal Mogul 8-7200CH-STD rod journal
Piston Ross custom, forged-aluminum, 4.211-in diameter, flat-top, 439.5 grams, 8.5cc reliefs
Piston to Deck Height Zero
Piston Pins Ferrea No. P70028-8, forged-alloy, 0.990-in diameter, 138 grams
Piston Rings Total Seal No. CR3455-65, plasma-moly, file-fit, 0.018-in gap
Fasteners ARP 194-5601 four-bolt main-stud kit
Balanced Yes
Oiling System
Windage Tray No
Crank Scraper No
Oil Pan Canton No. 15-450, road-race
Oil Pump Melling M54F
Oil Shell Rotella 30W
Heads
Casting Number Edelbrock No. 60569-2
Chamber Open, hand-smoothed
Combustion Chamber Volume 90 cc’s
Compression Ratio 9.95:1
Head Mods Fully ported intake and exhaust ports
Intake Port Volume Approx. 220 cc’s
Intake/Exhaust Flow Ratio 75 percent
Intake/Exhaust Flow at 28-in:
0.200 140/86 cfm
0.300 201/173 cfm
0.400 258/199 cfm
0.500 292/217 cfm
0.600 312/230 cfm
0.700 316/236 cfm
Intake Valve Ferrea No. 5073, stainless steel, 2.11-in, 5.100-in length
Exhaust Valve Ferrea No. 5144, stainless steel, 1.77-in, 5.100-in length
Angles Multi-angle with 45-deg seats
Retainers Comp Cams No. 740-16, 10 deg
Locks Comp Cams No. 611-16, 10 deg
Valvesprings Lunati No. 73100-16
Install Height 1.79 in
Seat Pressure 137 psi
Open Pressure 338 psi
Valveguides Bronze, 0.530-in diameter
Valve Seals Viton
Rocker Studs ARP No. 100-7101, 7/16-in
Rocker Arms Comp Cams No. 19060, full roller
Rocker Ratio 1.5:1
Pushrods Butler Performance No. SBR-581-R-16, 5/16-in diameter, 8.80-in length, chrome-moly
Fasteners ARP No. 190-3605 head-bolt kit
474ci Engine Build - Pump-Gas Poncho Power
Cam
Brand Comp Cams custom Butler grind
Type Hydraulic roller
Duration at 0.050 242/248-deg
Lift 0.540/0.562-in with 1.5:1 rockers
Intake Centerline Installed at 106.5 deg
Lobe Separation Angle 110 deg
Lifters Comp Cams No. 857-16
Timing Set Butler Performance No. JPP-5614LB-5, 0.005-in undersized, nine-way adjustable
Timing Chain Type Billet-steel roller
Distributor Driven Gear BOP No. PDG38, polymer, for MSD distributor
Induction
Carb Barry Grant Demon
Size 850 cfm
Mods None
Jets Front/Rear No. 81/89
Fuel Pump RobbMc No. 1006
Intake Manifold Edelbrock Victor No. 2957, modified by Butler Performance
Spacer 1-in phenolic, open design
Fuel Used for Test 92-octane BP
Ignition
Distributor MSD Billet HEI
Coil MSD in-cap
Wires MSD 8mm
Total Timing 40 deg
Spark Plugs NGK No. R5671A-7, gapped at 0.050 in
Exhaust
Headers Doug’s four-tube
Primary Diameter 1.75-in
Collector 3.00-in
Gaskets
Brand No. SPM-KSX703-74, complete Pontiac overhaul
At The Dyno
Conditions
Actual Air temp 74 deg F; Baro: 28.59-in of Hg; Humidity: 45 percent
Corrected To Air temp: 60 deg F; Baro: 29.92-in of Hg; Humidity: dry
Water Temp 195-deg
Oil Temp 195-deg
Corrected Dyno Results
RPM HP Torque
3,100 315 533
3,200 326 535
3,300 336 535
3,400 343 530
3,500 352 528
3,600 361 527
3,700 372 528
3,800 385 532
3,900 411 554
4,000 434 570
4,100 446 572
4,200 459 575
4,300 478 583
4,400 489 584
4,500 497 580
4,600 513 586
4,700 527 588
4,800 535 585
4,900 547 587
5,000 554 582
5,100 561 578
5,200 566 572
5,300 574 569
5,400 575 559
5,500 578 552
5,600 571 535
5,700 572 527
Pull Log
Pull 1: 81/89 jets; 40 deg; 577 hp at 5,400 rpm; 588 lb-ft at 4,800 rpm
Pull 2: 77/85 jets; 40 deg; 567 hp at 5,400 rpm; 585 lb-ft at 4,600 rpm
Pull 3: 77/85 jets; 38 deg; 564 hp at 5,300 rpm; 582 lb-ft at 4,700 rpm
Pull 4: 75/83 jets; 38 deg; 547 hp at 5,500 rpm; 568 lb-ft at 4,800 rpm
Pull 5: 75/83 jets; 35 deg; 547 hp at 5,300 rpm; 568 lb-ft at 4,600 rpm
Pull 6: 81/89 jets; 40 deg; 570 hp at 5,500 rpm; 586 lb-ft at 4,600 rpm
Pull 7: 81/89 jets; 42 deg; 578 hp at 5,500 rpm; 588 lb-ft at 4,700 rpm
Average Horsepower/Torque from 3,200 to 5,600 rpm
Pull 1: 470/559
Pull 2: 463/550
Pull 3: 463/550
Pull 4: 451/536
heres a different build
Pull 6: 468/558
Pull 7: 480/561
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