Single vs Dual pattern cam?

[cazsper]

From what I have read, is that the dual pattern cams are to make up for the shortcomings of heads in the exhaust side. But when it comes to aftermarket or ported and polished heads (if not both) is this really an issue? And.. How does a dual pattern cam compare to a single pattern cam? A common dual pattern cam for a Windsor for instance is 224/232 @ .050". Does that compare to a 224' single pattern cam, a 232' single pattern cam or something in the middle such as 228'?

 

[Tubo]

Ford heads are designed with high velocity small runners vs bigger runner to achieve flow volume. Some folks see this as a "short coming". Ever notice how Chebby valves tend to be a bit larger for a given engine displacement??

So even with high flow heads, a spit duration of 6-9 degrees is beneficial. There is no one correct cam answer of duration, lift, rocker ratio, as each combo must be a ballance of compromises for a specific desired application.(What is best for max HP@ hi RPM, isn't for max torque@ low RPM) On my AFR 185 headed 331 fer instance, I'm using a Lunati VooDoo 221/[email protected], .549/.565 lift, 112LSA. Which is a longer exhaust duration & lift than AFR's would usually need, cept I chose the wider split to help bleed off some dynamic compression ratio. My static CR is 10.8-11.0 which is getting to the high end of CR fer pump gas. Even with a CR of 9.3 I would choose a 6-7 split and .549 lift

Personally I could never understand why All the Ford Alphabet E-B-F-X-Z cams are single duration, cos Ford C5AE through GT-40X heads are in essence choked up on the exhaust side. Only the Ford 93-95 Cobra cam is a split duration.

IMHO all the pushrod windsor V-8's need a split ratio cam, irrispective of application.

 

[Tubo]

A common dual pattern cam for a Windsor for instance is 224/232 @ .050". Does that compare to a 224' single pattern cam, a 232' single pattern cam or something in the middle such as 228'?

Intake degrees to intake degrees

 

[cazsper]

So a 224/232 cam is equal to a 224/224?

 

[Tubo]

Equal? No! Absolutely not

Same class? Yes

Apples & Oranges are both fruit

 

[cazsper]

Would the dual pattern cam just be a broader RPM range?