Dyno Test 426 Hemi Sized Small Block (#11304)
This dyno test is an engine built for a street pounder, pump gas (92 octane), hydraulic roller cam, torque is king application. The engine was based on a standard 360 Magnum block (although it could just as easily been done with an "LA" block) and used the Edelbrock Magnum heads. The parts list is shown at the end of this article. We tested several different parts including intakes, carbs, cams, rockers, and oil pans. We had intended to put all the good parts together for a final series of tests, but dyno time ran out before we could get that done.
A pleasant surprise was that with our main girdle in place and using a stock oil pan we produced more power than with a popular name pan with a windage screen and scraper. Our main girdle acts as a scraper, too! Shown below is a table displaying the power curve and the volume efficiency curve.
|
EngSpd / RPM
|
Trq / corrected ft/lb
|
Power / corrected Hp
|
Vol. Eff.
|
|
3000
|
444.4
|
253.8
|
89.7
|
|
3100
|
440.3
|
259.9
|
86.1
|
|
3200
|
428.1
|
260.8
|
84.2
|
|
3300
|
424.5
|
266.8
|
81.8
|
|
3400
|
420.5
|
272.2
|
79.6
|
|
3500
|
416.9
|
277.8
|
77.2
|
|
3600
|
415.5
|
284.8
|
76.2
|
|
3700
|
415.1
|
292.4
|
76.1
|
|
3800
|
414.2
|
299.7
|
76.5
|
|
3900
|
425.6
|
316.0
|
77.9
|
|
4000
|
436.0
|
332.0
|
79.9
|
|
4100
|
453.3
|
353.9
|
81.8
|
|
4200
|
468.6
|
374.7
|
82.8
|
|
4300
|
484.8
|
396.9
|
85.5
|
|
4400
|
510.3
|
427.5
|
90.3
|
|
4500
|
521.2
|
446.6
|
94.1
|
|
4600
|
526.3
|
460.9
|
96.1
|
|
4700
|
530.7
|
474.9
|
97.9
|
|
4800
|
535.2
|
489.1
|
99.9
|
|
4900
|
537.4
|
501.4
|
101.1
|
|
5000
|
536.1
|
510.3
|
101.2
|
|
5100
|
533.0
|
517.6
|
102.3
|
|
5200
|
530.1
|
524.8
|
103.5
|
|
5300
|
526.1
|
530.9
|
103.3
|
|
5400
|
524.7
|
539.5
|
104.2
|
|
5500
|
515.8
|
540.2
|
102.8
|
|
5600
|
510.7
|
544.5
|
103.1
|
|
5700
|
506.1
|
549.3
|
102.5
|
|
5800
|
500.6
|
552.9
|
102.5
|
|
5900
|
494.0
|
554.9
|
101.7
|
|
6000
|
491.1
|
561.1
|
101.7
|
|
6100
|
483.5
|
561.5
|
101.6
|
|
6200
|
469.8
|
554.6
|
100.8
|
|
6300
|
468.0
|
561.4
|
100.0
|
|
6400
|
458.7
|
558.9
|
99.1
|
|
6500
|
447.3
|
553.6
|
98.2
|
Things to note: The torque was 444 ft/lbs from 3000 up and peaked at 537 and, remember, this is a small block! The horse power peak was 561 @ 6100, and the volume efficiency was over 100% from 4900 to 6300 RPM. The torque is up only about 100 ft/lbs over some 408/416 stroker kits we also show on our website. Awesome Baby!
The test results shown above were obtained using our HER6468AL camshaft, beehive valvesprings, a flow balanced 340 Victor Edelbrock intake, our 1.6 ratio rocker arms and the "wrong" oil pan combination.
This test was without the proper oil pan and scraper combination which added 12 ft/lbs and 10 HP maximum improvement. The oil also ran 10-12 cooler which confirms that windage was reduced. There were other tests that worked better than the parts installed in this test. I would expect this combo to be at least 580/585 HP and 560/565 torque with this basic heads, camshaft and intake combination and, again, this is a small block!
Some additional things to consider: This engine has much more power and torque than the original 426 Hemi engines. Sure you can build the Hemi to produce much more, and the reason is airflow. You will never get a set of small block heads to flow what Hemi heads flow.
With this many cubic inches, we are getting to the point where the common and popular heads are not going to flow enough air to make the power numbers that this amount of cubic inches could produce. The engine was originally designed to be a torque monster for street/strip use and with 536 ft/lbs torque, we have achieved that.
Note the torque @ 3000 of 444. We had one test combination (Test #2 below) that was 470 @ 3000 with a maximum of 542 ft/lbs torque and 534 HP. With this much torque, this low down in the RPM range it is difficult to test, but it would be safe to assume that the torque is well over 300 ft/lbs @ 2000.
|
Engine RPM
|
Torque
|
Power corrected
Horsepower
|
Volumetric
Efficiency
|
|
3000
|
469.8
|
268.4
|
88.7
|
|
3100
|
458.3
|
270.5
|
87.0
|
|
3200
|
452.7
|
275.8
|
85.6
|
|
3300
|
449.6
|
282.5
|
84.6
|
|
3400
|
449.7
|
291.1
|
84.5
|
|
3500
|
449.4
|
299.5
|
847
|
|
3600
|
450.7
|
308.9
|
83.5
|
|
3700
|
459.4
|
323.6
|
85.4
|
|
3800
|
453.9
|
335.6
|
86.7
|
|
3900
|
474.8
|
352.5
|
87.5
|
|
4000
|
489.9
|
373.1
|
90.3
|
|
4100
|
503.4
|
393.0
|
93.3
|
|
4200
|
511.6
|
409.1
|
93.8
|
|
4300
|
524.0
|
429.0
|
95.7
|
|
4400
|
527.5
|
441.9
|
96.2
|
|
4500
|
534.5
|
458.0
|
98.0
|
|
4600
|
540.1
|
473.0
|
100.0
|
|
4700
|
541.9
|
484.9
|
101.2
|
|
4800
|
541.0
|
494.4
|
101.9
|
|
4900
|
535.8
|
499.8
|
102.4
|
|
5000
|
531.6
|
506.1
|
102.5
|
|
5100
|
533.0
|
517.9
|
102.9
|
|
5200
|
525.1
|
519.9
|
103.1
|
|
5300
|
522.1
|
526.9
|
103.8
|
|
5400
|
509.1
|
523.4
|
102.8
|
|
5500
|
508.2
|
532.2
|
103.2
|
|
5600
|
497.2
|
530.2
|
103.0
|
|
5700
|
492.2
|
534.2
|
101.8
|
|
5800
|
482.4
|
532.7
|
101.69
|
|
5900
|
473.6
|
532.1
|
101.1
|
|
6000
|
445.1 |
508.5
|
99.4
|
The test shown above used our HER4246Al cam, beehive valve springs, our flow balanced 340 Victor Intake , our 1.6 roller rocker kit and again, the "wrong" pan combination.
A torquey engine is a lot of fun to drive on the street. It will be very throttle responsive and quick accelerating because of the torque. For a truck or heavy weight street cruiser this would be a tire destroyer at the tip of your toe, and it is a pump gas small block or at least it looks like one. Speaking of looking like a small block, we could probably duplicate these power numbers with our fully ported Heavy Duty Magnum heads, and you could install the old 340 valve covers and it would look like a stock 340 with an intake and headers. Looks can be deceiving!
426 c.i "Hemi-sized" Small Block Basic Parts List:
360 Magnum Block - P/N HUG KITBLOCKSB
Modifications which allowed the use of a standard oil pump P/NKITBLOCKSB
426 c.i. stroker kit, forged pistons, forged crank, H beam rods P/N HUG 426-RACE-KFH
360 Main bearing girdle P/N HUG 7382K (Edelbrock Magnum heads with StageIII porting--Head drilled for L.A. intake)
Bolts, ARP for Magnum heads P/N ARP 144-3605
Hughes Rocker arms 1.6 ratio with poly-locks
Pushrods oil thru chromoly, hardened for use with guide plates P/N5260
Camshafts tested: Hydraulic rollers HER3642AL, HER4246AL, HER6468AL
Intakes tested: RPM, 340 Victor, Super Victor
(intakes were tested both stock and deep port matched with balanced flow)
RPM Intake (air gap style) P/N EDE 7576 340 Victor P/N EDE 2915
Super Victor P/N EDE 2815
NOTE: These are L.A. intakes that could be used with the Magnum heads
because the L.A. bolt pattern was drilled into the Magnum heads.P/N1196
for iron heads and P/N1197 for aluminum heads
Timing chain ProGear, Double roller with the 7 key way cam-dex cam sprocket
where all cam adjustments are made from the cam sprocket (much
easier than the crank sprocket) P/N HUG 6442
Tensioner, timing chain P/N CLO 9-5387
Pan, oil Stock style, Ram truck P/N HUG 6101
Moroso (modified for use with main girdle) rear sump per customer P/N MOR 20732
Carb Demon 750
Spring, valve, double spring P/N HUG 1129
Beehive style P/N HUG 1122
Damper BHJ P/N64816
Dipstick, quick disconnect (Piercy type)
Pump, oil, Standard pressure, standard volume P/N MEL M72
Small blocks are not known for their grunt and torque. However, this one blows all those beliefs out the window. This small block meets or exceeds some well-built 440 big blocks. If you love small blocks and want big block power and torque, here is what you are looking for!
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