It has come up in discussion many times about the effects a ratio rocker has on a cams duration. Here are my findings on an engine I am currently building for myself. The cam is an Engle 120 with a duration of 253* @ .050" AT THE LIFTER. Mine came in just shy of that number with a reading of 252* @ .050". I am running Pauter 1.3:1 ratio roller rockers on this combo that actually spec out to a 1.36:1. My duration reading at the valve was 261* @ .050" ! That is a whopping 9* increase in duration with only a 1.36:1 rocker arm. I imagine that going on up to a 1.4:1 or 1.5:1 would add somewhere between 2 and 5* more to that figure depending on the actual ratio. These are my findings on one particular application and will surely vary on every combo.

thanks for posting aaron

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Just Stand On It!!!!

Chris

Thanks for sharing.

thanks aaron.. guys like you that go out of your way to sit down, figure why and how and then give an accurate answer to educate the masses.. thats what keeps me and others coming back

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x2

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Hey,can you hand me those zip ties and that roll of duct tape?!

Thanks Arron, One of the best things about this site is the diversity of builds be it engines, parts, transmissions. I was lucky to have an extremely knowledgable Shop in my area with a vast knowledge of the latest and greatest. Again thanks for posting.

I don't even run an AC but enjoy learning more about the hobby.

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Water Cooled Consortium, Chairman of the Build (Former AC purist)

So if I'm looking at this rite running a w110 with 1.5 rockers is like running a FK44 with 1.5 rockers or close to.