My junk (most of it):
Here are the goods on the head I got from Howard Davis. This is the head he was running before he made his billet head:
Valve sizes are: Exhaust - 1.45 and Intake - 1.70
Chamber volume=50cc
Lift....Intake@28"....Exhaust@28"......Ratio..E/I
200.....116.60.............95.00...............81%
300.....158.12............133.56..............84%
400.....177.00............158.12..............89%
450.....185.26............159.30..............86%
500.....188.80............159.30..............84%
550.....189.98............159.30..............84%
AVG:...169.29............144.10..............85%
Compared to the Norm Foster head flowed on the same bench:
Valve sizes are: Exhaust - 1.55 and Intake - 1.83
Chamber volume=45cc
Lift....Intake@28"....Exhaust@28"......Ratio..E/I
200.......89...................70................78.6%
300......137.................107................78.1%
400......174.................122................70.1%
450......187.................126................67.4%
500......195.................129................66.1%
530......198.................131................66.2%
550......195.................131................67.2%
600......184.................132................71.7%
AVG:...169.87.............118.50............69.7%
And the Gary Bruner head flowed on a different bench at 25"
(Seymour's Notes)
Valve sizes are: Exhaust - 1.45 and Intake - 1.78
Chamber volume=47cc
Lift....Intake@25"....Exhaust@25"......Ratio..E/I
200.....102....................93.................91%
300.....150...................141................94%
400.....183...................160................87%
500.....192...................169................88%
600.....201...................177................88%
700.....205...................181................88%
AVG:...172.16..............153.50............89%
And the milder Gerald Wright head on GodsRods Duster II (Also flowed by Gerald on the same bench as the Davis and Foster heads):
Valve sizes are: Exhaust - 1.36 and Intake - 1.62
Chamber volume=53cc(?)
Lift....Intake@28"....Exhaust@28"......Ratio..E/I
200.....103....................85.................83%
300.....143...................102................72%
400.....160...................110................69%
500.....168...................118................70%
600.....168...................118................70%
700.....168...................118................70%
AVG:...151.66..............108.50............71.5%
And last, but not least (well, actually it is the least
) is the same head as above before Gerald cleaned up the ports a little bit.Valve sizes are: Exhaust - 1.36 and Intake - 1.62
(I think he flowed it after the valve size increase, but these numbers may be completely stock, can't remember now)
Lift....Intake@28"....Exhaust@28"......Ratio..E/I
200......90.....................87.................90%
300.....129...................104................81%
400.....141...................110................78%
500.....148...................113................77%
600.....148...................113................77%
700.....148...................113................77%
AVG:...134...................106.66...........79.6%
