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Aug 18, 2009 | 04:01 AM

cgEvan

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From: Georgiaaaaaa

Rocker question

Could I just upgrade my rockers to 1.6 ratio or 1.7 ratio and gain lift/duration? When I had my 5.0 Mustang, I read a write-up of a magazine doing AFR 185 heads, headers, intake, and 1.7 ratio rockers on the stock cam/bottom end, and making XXXhp (I want to say something high, around 400hp).

Thanks.

Aug 18, 2009 | 04:12 AM

JB_97ws6TA

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From: Central Valley, CA

you can gain lift but the duration is ground into the cam, that is not going to change. I am not sure what the factory cam lift numbers are and i doubt that the stock springs would be able to handle the added lift but I am sure someone who has more info on this subject will be able to chime in but to answer your question yes you can add lift by changing rockers but your duration remains the same

Aug 18, 2009 | 04:33 AM

gregrob

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From: 6,000+ feet

Yes you will pick up some power from the added lift. You will need new valve springs

Aug 18, 2009 | 09:03 AM

97badass

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From: Hillsboro Kansas

sorry to hijack the thread but... how much do you gain with the stock cam and 1.7 RR?
i think he is also trying to figure this out.

Aug 18, 2009 | 10:34 AM

lt1srule

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From: ORLANDO .FLORIDA

you will need springs .stock springs suck ..

Aug 18, 2009 | 12:12 PM

97badass

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From: Hillsboro Kansas

we know we need new springs as well. with new springs and 1.6's dont you gain like 10-20 hp? so with 1.7 shouldn't you gain like 15-25?

Aug 18, 2009 | 12:40 PM

Wooshie

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From: Elwood,il

Quote:

Originally Posted by JB_97ws6TA

Duration is ground into the cam , but since your valvetrain geometry changes it does affect duration (Like 1-2 degrees)

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Aug 18, 2009 | 01:32 PM

97badass

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From: Hillsboro Kansas

Quote:

Originally Posted by ss.slp.ls1

I think a conservative number, ~15rwhp, is what I would expect from 1.7rr's and springs.

ok i just figured with a slightly bigger rocker you would gain more power

Aug 18, 2009 | 06:48 PM

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JB_97ws6TA

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From: Central Valley, CA

Quote:

Originally Posted by Wooshie

Duration is ground into the cam , but since your valvetrain geometry changes it does affect duration (Like 1-2 degrees)

I am not too sure about that, your geometry really isn't changing you just have increased rocker ratio but your lifter rides up and goes back down at the same time as it always would have, your pushrod would still rise and fall as it always had, your rocker would open and close as it always had with the exception of an increased multiplication of lift at the valve but other than that everything remains the same does it not?