BuiltWithNOF
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Cylinder Head Porting, Antique and Hi-Performance American Motorcycles

porting for

Twin Cam 

Cylinder Heads

Erik's bike

valve lift

Stock Twin Cam int/exh

Screamin’ Eagle Factory CNC

Screamin’ Eagle   MCR          int/exh

Lee’s Torque Port    in/exh

Lee’s Power Port Plus

Stock Screamin’ Eagle 110

Lee’s  S.E. 110 Torque Port

.100

60/55

69/49

58/57

60/49

68/52

66/60

66/58

.200

138/113

129/113

122/113

126/109

144/114

141/120

144/124

.300

187/154

202/163

182/157

192/160

205/150

198/162

210/171

.400

215/180

247/196

228/195

240/203

262/188

243/189

265/205

.500

226/194

259/215

242/213

270/220

290/218

264/204

304/230

.600

231/204

260/225

242/219

282/227

298/237

272/211

322/243

.650

229/201

260/227

240/221

285/230

301/241

275/212

328/248

flow figures are based on testing on our SuperFlow SF600 flow bench @ 28” test pressure.  Results may vary slightly due to differences in casting between heads of the same type

As can be seen from the above chart, there is potential for major improvement, both in the stock Twin Cam castings and the Screamin’ Eagle heads.  We have recently streamlined our process and now offer two different types of port job.

  The “Torque Port” is a great upgrade for your stock heads and gives the biggest bang for the buck.  It flows more than enough to support well over 100 rear wheel horsepower and 100 ft lbs of torque on a 95 inch (more on a 103) using your stock head castings.  Likewise the “Torque Port on Screamin’ Eagle 110 heads will support over 130 horsepower (we have seen 128 horse at the rear wheel using a fairly mild cam of only .560 lift;  we have also seen 141 horsepower from the same porting with a slightly hotter cam).

 For those of you seeking even more performance we offer the “Power Port.” Larger intake valves and more intensive porting make this the choice for high revving/ high horsepower motors.

Click the links to your left for more information on these porting jobs for either Screamin’ Eagle or stock Twin Cam castings.