1.5 or 1.6

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stroker mike

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If you have a small block with a mild cam, in this specific example it is a 204/216 with 427/454 respectively, adv 260/272, with 1.5:1 rockers, with an increase in rocker ratio it will show 455/484 at the valve, that is like one of the smaller voodoo or xe grinds in effect, right? my question is, what will it do to the power band? right now I get power from 1200-4800/5000 but with additional lift that range will slide up a little, right? an airgap will do better on that than my performer, right? cause it seems much more punchy than a performer cam now, and the increase in ratio would only add to that I bet, while still giving lot's of vacuum and decent economy, too. I know that these 904 tappets can take the increase in rate of lift with no problem, could someone give me an idea of what I could really expect? :thumbup: thank you. I am working on another project until I can get my big block machined. gotta stay busy, you know, idle hands are wasted horsepower!
 
I like the 1.6 ratio because it gives back most of the lost motion (lift) lost in the poor valve geometry the small Mopar has. Actually, .427 will yield a true lift @ the valve installed .440. And .454 yields, a true lift of .468 @ the valve. This is for hyd. cam, mechanical will be less than this after lash is introduced. Duration @ .050 will increase only slightly, 1.5 degrees or so. Good luck, Terry.
 
I took the gross lift, divided by 1.5, then multiplied by 1.6 is how I got the figures I came up with. where does the valve geometry loose so much and how can I fix it? does the ratio actually behave like a 1.55 with a 1.6 rocker? does it depend on the brand of rocker? I want true lift, that is for sure, and if I have to I will just do a cam swap but that would be a shame cause this setup is new. I wanted to upgrade the rockers any way, so I thought I could get away with a ratio change to get it up to where I want it.
 
You cant fix the lifter angles. It's unfortunately one of the things Mopar didn't do really well. But is serves it's purpose. You will lose I think in the neighborhood of .020" thru the poor angles.
 
Raising ratio causes valvetrain loads to go way up. Given the choice, do it all with the cam.
 
Well, I guess I will have to get on the phone for a new grind quick, the motor is supposed to go back in in two weeks. ](*,)
 
I have an early Holley Street dominator I will be selling shortley. It has the 273-318 ports.
:coffee2:
 
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