These are test results from our flowbench, built in-house by us to test our head port designs. These tests were all done on the same bench with the same correction factors for atmospheric density, temperature, and an 8% overall reduction in final numbers to conform with orifice test plates used for calibration and other known heads flowed on calibrated benches with published results. We are publishing these results to help you make better purchasing decisions and further your understanding of internal combustion engine performance.
Although we have made every effort to ensure that these results are accurate, the data generated from these and continuing tests is best interpreted by comparing different heads on the same flowbench. We understand other's skepticism and welcome real world testing of our products at a racetrack with timing equipment by knowledgeable racers and engine builders. All of these tests were conducted at 15" of water depression.
Note that this table does not include port velocity data, which strongly influences the power output derived from the indicated airflow
| Cylinder Head Designation | .050" | .100" | .150" | .200" | .250" | .300" | .350" | .400" | .450" | .500" |
| Duromax 440 35mm x 5.5mm valve | 29.1 | 50.3 | 73.1 | 93.4 | 103.4 | 106.1 | 110 | 112.6 | ||
| Ducar DH420 casting DB-5 36mm x 6.6mm valve | 26.5 | 51.7 | 76.9 | 94.2 | 101.4 | 104.8 | 107.4 | 110 | 111.3 | 111.9 |
| JT-97 36mm x 6.6mm valve | 29.1 | 53.1 | 76.9 | 96.4 | 104.8 | 108.7 | 112.6 | 115 | 116.9 | 118.1 |
| Our secret, but it's a stock head | 37.2 | 58.9 | 84.9 | 111.7 | 133.2 | 144.7 | 150.8 | 150.8 | 150.8 | 149.9 |
| R500-D 38.5mm x 5.5mm valve | 29 | 51.7 | 75 | 97 | 111.2 | 115.5 | 118.5 | 119.7 | 120.9 | 123.2 |
| Predator 420 Hemi Head 38mm x 6.6mm Intake | 29 | 52.9 | 78.5 | 100.4 | 109.1 | 111 | 111.6 | 112.3 | 112.9 | 113.5 |
| Predator 459 / Loncin LC192FD | 23.6 | 50.1 | 78.3 | 100.2 | 108.3 | 109.5 | 110.8 | 112.1 | ||
| Blackmarkit Innovations MoFlow BB | 50.1 | 78.3 | 115 | 144.1 | 175.2 | 194 | 207.9 | 218.4 | 222.8 | 225.9 |
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