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.
| 
