#4---Feb 2008 Small Block 426 Stroker Dyno Test

12/23/2014
Dave Hughes


426 SMALL BLOCK DYNO TEST

FEB 2008 (PPC) 

 

 

We dynod this 426 small block engine with a goal of 600HP on pump premium 92 octane gas. We made that with about 20HP to spare. One very interesting point to note is that torque came up right along with the horsepower and peaked at over 600 ft lb. We tried some new oil pan designs with great results, along with some carb spacers that showed more good results.
 

ENGINE DESCRIPTION

 

Block: 360 Magnum (shop core)

            Race prepped, p/n HUG KITBLOCKSB
    
        Main stud girdle (w/studs) p/n  HUG 7382K
Stroker kit:  426 Hemi-sized small block kit, p/n HUG 426-RACE-KFH  Complete with crank, rods, pistons, rings, chamfered bearings and internal race-balanced.

Oil pan: Hughes Experimental

Cylinder heads: Edelbrock Magnum aluminum with our Stage 3 Fat Flow porting

Valve Springs: Hughes beehive (p/n HUG 1122) with  beehive retainers (p/n HUG 1286R)

Rocker arms: Hughes fully rollerized 1.6:1 ratio (p/n HUG 1560)
Camshaft: Hughes Engines Hydraulic Custom Roller (p/n HER6468AL-7)

Intake Manifold: Edelbrock Super Victor with our deep port match (p/n HUG 2815DPM)

Carburetor: 750 Holley. Note: this size is too small for an engine of this displacement.

               A 950 CFM would have been a better choice.

            

All of the parts were coated with specific coatings, depending on their locations and function.

Crankshaft: oil shedding and lubrication on the journals

Connecting rods: oil shedding

Pistons: heat reflecting, oil shedding, friction reduction

Bearings: protection and friction reduction

Camshaft: friction reduction and protection

Cylinder heads: heat dissipation, port insulation, heat reflection in the chambers

Valves: heat protection and friction reduction

Springs: heat dissipation and oil shedding

Girdle: oil shedding

Block: heat dissipation and oil shedding

The guys at Professional Powder Coating thought the coating should be worth 25-45 HP. If we built an engine similar to some of the 550 HP Hemi-sized small blocks, we should be able to attain 600 HP with a hydraulic cam and pump gas.

 

We used 1 headers, which are definitely too small, but that is the biggest ones currently available. We are probably loosing 10-15 HP right there. Well soon see!
 
         

We first tested the engine with a stock 360 oil pan and a 1 open carb spacer.

 

Chart #1

Note in this test, and all of the following tests how the torque and horsepower peak numbers are very close. 

 

EngSpd / RPM

Trq / corrected ft/lb

Power / corrected Hp

3000

 

 

3100

 

 

3200

421.8

257.0

3300

425.7

267.5

3400

427.6

276.8

3500

446.7

297.7

3600

449.0

307.8

3700

450.9

317.7

3800

468.0

338.6

3900

477.7

354.7

4000

495.3

377.2

4100

512.3

399.9

4200

532.7

426.0

4300

543.9

445.3

4400

548.3

459.3

4500

558.5

478.6

4600

561.9

492.1

4700

561.4

502.4

4800

566.3

517.5

4900

561.9

524.2

5000

558.0

531.2

5100

555.6

539.5

5200

544.3

538.9

5300

539.9

544.9

5400

529.8

544.7

5500

519.0

543.5

5600

522.0

556.5

5700

509.3

552.7

5800

505.8

558.6

5900

506.8

569.3

6000

492.7

562.9

6100

488.3

567.2

6200

478.5

564.9

6300

469.8

563.5

6400

457.1

557.0

6500

444.9

550.6

 

RPM Range 3200-4700
Average 3950                        492.6                         374.9
Min       3200                         421.8                         257.0
Max      4700                         561.9                         502.4  
          

Chart #2 

Check this out: 45HP at 6500RPM and 37 ft lb at 6500 RPM 
 
 

         
RPM Torque Change HP Change Vol Eff %

3100

429.2

 

253.3

 

77

3200

433.2

+12

264.0

+7

75.4

3300

437.3

+12

274.8

+7

74.2

3400

437.3

+10

283.1

+7

73.6

3500

441.1

-5

294.1

-3

73.5

3600

448.9

0

307.7

0

74.3

3700

460.0

+10

324.1

+7

76.3

3800

473.6

+5

342.6

+4

76.9

3900

498.6

+21

370.3

+16

82.2

4000

501.1

+6

381.6

+4

82.9

4100

515.2

+3

402.2

+3

84.1

4200

538.3

+6

430.5

+4

87.1

4300

555.3

+12

454.7

+9

91.5

4400

562.2

+16

471.0

+12

92.4

4500

577.3

+22

494.6

+16

94.8

4600

572.3

+11

501.3

+9

96.1

4700

572.9

+12

512.7

+10

96.0

4800

589.4

+24

538.7

+21

98.1

4900

580.9

+19

542.0

+18

97.0

5000

586.0

+28

557.9

+26

97.6

5100

583.3

+28

566.4

+27

98.6

5200

571.8

+27

566.1

+28

98.5

5300

565.3

+26

570.4

+26

98.0

5400

559.4

+30

575.2

+31

97.7

5500

549.0

+30

574.9

+31

97.4

5600

545.5

+23

581.7

+25

96.6

5700

535.1

+26

580.7

+28

95.9

5800

534.6

+29

590.4

+32

96.0

5900

528.3

+22

593.5

+25

95.3

6000

520.5

+28

594.7

+32

94.4

6100

516.6

+28

600.0

+33

93.9

6200

505.5

+28

596.8

+32

93.4

6300

497.6

+28

596.9

+33

92.4

6400

487.7

+30

594.3

+37

91.3

6500

481.3

+37

595.7

+45

90.0


Average          519.8                                 479.4
Minimum         429.2 (3100 RPM)            253.3
Maximum        589.4 (6500 RPM)            600.0

We tested one design of our custom oil pan YOWZERS!. This is a special pan that we designed to work in conjunction with our main stud girdle (scraper). Note that power was up at all RPMs from 3200 RPM and up. It obviously started at a much lower RPM because it was 12HP and 7 ft lb tq better at 3200 and went up from there. This is unusual as most wet sump systems dont start to help until 4000 RPM or more. This is free horsepower (a lot of free horsepower). 

 

Chart #3
 

 

RPM

Torque

HP

Vol Eff%

3100

430.2

253.9

78.0

3200

425.2

259.1

76.2

3300

410.8

258.1

75.0

3400

428.3

277.2

74.3

3500

433.3

288.8

74.4

3600

442.8

303.5

75.6

3700

453.3

319.4

76.4

3800

473.3

342.4

79.4

3900

482.8

358.5

81.6

4000

500.8

381.4

83.9

4100

525.8

410.4

86.5

4200

542.3

433.6

89.0

4300

552.3

452.2

91.7

4400

544.4

456.1

93.2

4500

561.9

481.4

94.0

4600

571.9

500.9

95.6

4700

568.7

508.9

96.4

4800

573.3

523.9

96.7

4900

573.3

534.9

97.7

5000

572.8

545.3

97.7

5100

569.9

553.4

98.7

5200

559.2

553.7

98.2

5300

559.3

564.4

98.2

5400

552.8

568.4

98.0

5500

544.9

570.6

97.6

5600

539.4

575.2

96.5

5700

529.6

574.7

96.1

5800

527.4

582.5

96.0

5900

519.6

583.7

95.5

6000

512.1

585.0

95.1

6100

508.7

590.8

93.9

6200

502.3

593.0

93.0

6300

491.4

589.4

92.5

6400

483.5

589.2

91.8

6500

473.7

586.2

90.3

Average:    4800                    512.6                    472.9                       89.8
Minimum    3100                    410.8                    253.9                       74.3
Maximum   6500                    573.3                    593.0                       98.7

Not being able to leave a good thing alone, we further modified the oil pan and lost power, however, notice the power was still greater than with the stock oil pan and it too continued to increase in the higher RPM ranges. This pan was considerably different that the pan in test#2 and had features that had shown power increases in other tests. Unfortunately, it had some other features that resulted in power losses, which more than offset the gains. The price of progress is bathed in failure. 

 
       We show the test for two reasons;
1. Tests dont always produce positive results
             and ....
2. The next tests with carb spacers are based on the pan in this test.

 

Chart #4

 
RPM
Torque
HP
Vol Eff%
3100
447.2
264.0
76.8
3200
446.8
272.2
74.9
3300
444.8
279.5
74.6
3400
445.8
288.6
73.3
3500
448.8
299.1
73.2
3600
454.4
311.5
74.3
3700
466.4
328.6
77.1
3800
473.9
342.9
77.7
3900
494.0
366.8
80.4
4000
520.1
396.1
82.5
4100
543.4
424.2
86.6
4200
552.9
442.1
89.1
4300
564.5
462.1
92.1
4400
574.2
481.1
93.9
4500
578.5
495.7
94.2
4600
580.0
508.0
94.7
4700
588.0
526.2
97.1
4800
591.2
540.3
98.4
4900
590.7
551.1
99.3
5000
586.7
558.6
99.6
5100
585.1
568.1
100.0
5200
576.1
570.4
99.5
5300
567.7
572.9
98.3
5400
561.7
577.5
98.2
5500
556.3
582.6
97.4
5600
545.4
581.5
96.7
5700
544.0
590.4
96.8
5800
538.5
594.7
96.0
5900
536.1
602.2
95.6
6000
528.7
604.0
95.1
6100
524.3
608.9
94.8
6200
511.2
603.4
93.8
6300
507.3
608.5
93.1
6400
490.4
597.6
92.0
6500
479.9
594.0
90.9

Avg    4800                527.0                  485.6                        89.9
Min    3100                444.8                  264.0                        73.2
Max   6500                591.2                  608.9                       100.0
 

We tried some different carb spacers.
This test is representative of the results that we saw with a 2 taper-styled spacer. Compare these numbers to chart #3. We tested a similar tapered spacer that was only 1 thick. Its numbers were only about 3-5 below that of a 2 spacer. These results may not be the same with all carb/intake/engine combinations, but with ours, it showed considerable power increase at all RPM levels. The power curve was smoother too. Also note how the volumetric efficiency has improved with the spacer, further proof that better breathing (such as the carb & headers mentioned earlier) are keys to more power.

                 

 

Chart #5

 
RPM
Torque
HP
3100
457
271
3200
466
284
3300
465
292
3400
464
294
3500
457
306
3600
462
316
3700
486
333
3800
485
346
3900
510
378
4000
531
404
4100
565
433
4200
563
446
4300
574
471
4400
592
496
4500
591
506
4600
587
514
4700
599
536
4800
608
556
4900
608
569
5000
601
569
5100
609
590
5200
599
592
5300
575
579
5400
570
585
5500
565
591
5600
552
588
5700
556
602
5800
549
606
5900
549
617
6000
539
617
6100
536
623
6200
518
611
6300
521
621
6400
495
604
6500
487
604

 
This one is all of the good results added together and divided in half. This is called realistic/over wishful thinking, and these are used to generate realistic test results with all of the improvements at one time. We couldnt actually do this test, as our best pan was changed.  

    

Final Thoughts

With our best oil pan design, a 950 carb, stage 2 intake and 1 7/8 headers, it would be safe to think that 650 HP is possible with a 426 Hemi-sized Small Block running on pump gas. Note that the volumetric efficiency only reached 100% at one point which indicates the need for larger headers and carburetor. This also indicates that 600 HP with a much smaller cam should be possible for some more streetability. As if 457 ft lb of torque at 3100 RPM isnt streetable from a pump-gas, hydraulic-cammed, Hemi-sized small block! Get real friendly with your tire dealer! You will need plenty. 

    

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