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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/or Porter 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 Steve Magnotty 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.
 
Buick Exhaust Flow Comparison
Engine, Valve Size and Porting Status Tester and/or Porter 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 52.0 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