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Head Flow Comparison

 



Flow bench #s can be deceptive. If you have a set of heads flow benched and they don't match advertised cfm it can be from testing methods and differences in the benches. Possibly newer benches are more accurate but could also be the manufacturer padding the #s of their product to make it look better.  You be the judge


Stock Magnum 5.2/5.9 hds vs Heavy Duty heads

 & RT 2.02 Mopar heads

Hughes Engines and EQ Cylinder head sell the Heavy Duty heads (flow chart from Hughes)

 

www.hughesengines.com/heavyduty

www.eqcylinderheads.com/flow.html

Valve
Lift

Intake

Exhaust

 

OEM

Heavy
Duty

R/T

OEM

Heavy
Duty

R/T

 

1.920"

1.920"

2.02"

1.60"

1.60"

1.650"

 

0.100"

51.2

68.2

61.4

55.1

57.2

65.9

 

0.200"

121.1

124.1

119.2

109.0

114.1

120.2

 

0.300"

181.5

179.6

169.3

148.4

155.3

153.7

 

0.400"

207.5

213.8

211.0

170.8

180.0

168.0

 

0.500"

209.0

227.0

220.6

176.2

187.3

174.0

 

0.600"

208.4

233.1

220.6

178.4

188.7

176.0

 

 

 

 

 

 

 

 

 


Stock Magnum 5.2/5.9 hds vs Edelbrock Performer RPM alum 2.02heads

INTAKE PORT CFM

LIFT

STOCK

EDELBROCK

0.100

60

62

0.200

120

119

0.300

168

175

0.400

195

225

0.500

202

251

0.600

194

260

EXHAUST PORT CFM

LIFT

STOCK

EDELBROCK

0.100

59

52

0.200

113

105

0.300

142

142

0.400

148

169

0.500

150

185

0.600

151

190

Info source

EDELBROCK Corp.
2700 California St., Dept PHR
Torrance, CA 90503
(310) 781-2222
www.edelbrock.com

Flow benches all show different #s on the out of the box Eddy heads depending on the machine shop. Here are what some got for the base flow rates @ 550Lift & 28" though Ill be running .580 lift on the intake side with the new cam.

Edelbrock got 256/187cfm approx

Hughes Engines got

236/186cfm @ 550

My machine shop got 200/156cfm


My Eddy heads out of the box flowed 200in/156cfm @550 lift  before porting This is how the Eddy heads now flow after stage III porting, gasket matching & 3 angle valve job & decked. Before and after port work flow gains are 23% on the intake side and 36% on the exhaust side. That is a pretty large increase in flow over out of the box.  Based on Hughes Flow bench that is 290/253cfm, on the Edelbrock bench these heads would flow 317/254cfm!

 

                        


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