All, I have a quick question that I'm sure a lot of you can answer. I'm getting ready to buy new rocker arms for my 283. I,m going to get the roller tip 1.6 ratio instead of the stock ratio. My question is what benifit do I get with the 1.6 ratio I am assuming a little higher lift and duration,is that right?
Just make sure your pushrods don't rub inside the pushrod holes in your heads after installing the new rockers... Oh to answer your question, yes a little higher lift and maybe 1 degree more duration.
Comp Cams says that the 1.6 ratio on a cam manufactured with 1.5 rockers in mind (as most cams made for Chevy are) adds .035 lift and every tenth over that adds another .035 lift. Now I'm assuming that you had 1.5 ratio. Also, With the roller tip it just makes the valvetrain run smoother. The only downfall is adjusting them which isn't that bad if you know how to do it. I for one don't know how as I have never owned a set myself but, I know lots of people that do. You might have to have guide plates for your pushrods which would probably be a bolt on for sbc. And with the guide plates you need heat treated pushrods.
Also important to confirm pushrod length. Check with light springs on #1 cylinder. Geometry will change with different ratio roller rockers. The FOGGER
Nominal duration does not change. Full lift duration does not change. At every other point, the lift at any specific duration is greater, and the duration at any specific lift is greater.
If you know the actual lobe lift of the cam you can do the math to see how much your gross lift will change. This link tells you how to do that. gross valve lift is what you see on the cam spec like .685, lobe lift is the cam itself .4032 http://www.compcams.com/Technical/FAQ/FAQRockerArms.asp
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