Buick 401 and 455 Head Porting Chart
This is an interesting flow comparison for various Buick head, valve and porting combinations. I own or owned most of the heads involved and have the flow sheets. Some were before and after porting #s of the same head. All flow #s were at or converted to flow @ 10" of water. Multiply any of the #s by a 1.67 conversion factor to get the flow @ 28" of water (industry standard). I just happened to have more flowed at 10" than 28", and I had to go one way or another for comparison
Steve Berry
| Buick Intake Flow Comparison |
| Engine, Valve Size and Porting Status | Tester and/orPorter | Water | Conv. Factor | .100 Lift | .200 Lift | .300 Lift | .400 Lift | .500 Lift | .600 Lift |
| 401, 1.87, None | Mike Kamm | 10” | / 1.67 | 53.4 | 110.2 | 157.0 | 180.4 | 190.4 | 195.4 |
| 401, 1.94, None | Steve Magnotty / Carmen Faso | 28” | NA | 58.9 | 119.0 | 164.0 | 179.4 | 183.0 | 184.0 |
| 401, 1.87, Medium | Mike Kamm | 10” | / 1.67 | 56.8 | 111.9 | 158.7 | 192.1 | 210.4 | 202.1 |
| 401, 1.87, Moderate | Greg Gessler | 10” | / 1.67 | 61.6 | 7127.1 | 170.7 | 196.6 | 211.9 | 219.1 |
| 401, 1.94, Moderate | SteveMagnotty | 28” | NA | 61.0 | 121.0 | 172.0 | 201.4 | 215.0 | 223.0 |
| 455, 2.12 None * | Charlie Evans | 28” | NA | 76.1 | 142.0 | 197.7 | 226.8 | 224.9 | 226.8 |
| 455, 2.12, Street/ Strip | Greg G. / G. Tomlenson | 10” | / 1.67 | 70.8 | 138.1 | 200.0 | 238.1 | 244.7 | 245.5 |
| 455, 2.12, Competition | Greg Gessler | 10” | / 1.67 | 71.0 | 146.0 | 212.6 | 258.9 | 270.5 | 264.4 |
| 525, 2.25, Stage IV | Mike M. (TA) / Champion | 28” | NA | 75.7 | 147.0 | 218.0 | 265.8 | 321.0 | 361.9 |
| * Earlier 430 heads with stage one 455 valves installed. The 430 featured larger intake ports than the 1970 and up stage one heads. |
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| Buick Exhaust Flow Comparison |
| Engine, Valve Size and Porting Status | Tester and/orPorter | Water | Conv. Factor | .100 Lift | .200 Lift | .300 Lift | .400 Lift | .500 Lift | .600 Lift |
| 401, 1.50, None | Mike Kamm | 10” | / 1.67 | 45.1 | 76.8 | 98.5 | 113.6 | 118.6 | 120.2 |
| 401, 1.50, None | Steve Magnotty / Carmen Faso | 28” | NA | 47.7 | 81.5 | 112.0 | 119.5 | 123.9 | 125.4 |
| 401, 1.50, Medium | Mike Kamm | 10” | / 1.67 | 40.1 | 78.4 | 101.9 | 121.9 | 131.9 | 131.9 |
| 401, 1.50, Moderate | Greg Gessler | 10” | / 1.67 | 48.3 | 82.7 | 108.0 | 130.4 | 138.1 | 141.4 |
| 401, 1.50, Moderate | Steve Magnotty | 28” | NA | 52.0d> | 93.0 | 126.0 | 141.0 | 150.0 | 153.0 |
| 455, 1.75, None | Charlie Evans | 28” | NA | 57.4 | 96.9 | 124.1 | 142.0 | 152.0 | 156.3 |
| 455, 1.75, Street/ Strip | Greg G. / G. Tomlenson | 10” | / 1.67 | 63.3 | 115.4 | 143.1 | 168.8 | 174.3 | 177.0 |
| 455, 1.75, Competition | Greg Gessler | 10” | / 1.67 | 60.6 | 119.2 | 145.3 | 172.3 | 187.5 | 195.1 |
| 525, 1.81, Stage IV | Mike M. (TA) / Champion | 28” | NA | 64.6 | 128.7 | 179.5 | 221.7 | 247.2 | 259.8 |
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