1.60 rocker ratio versus 1.65 rocker ratio

[TheSilverBuick]

I think I asked a similar question a while back but don't seem to recall the answer or thread if I did.

I intend on upgrading to roller rocker's this winter and have my choice between 1.60 and 1.65 ratio rockers. I'll be changing the cam at the same time so target total lift can be achieved via the cam grind alone (sub-.600").

Are there advantages of simply having more or less rocker ratio other than gaining more lift? Longevity? Noise? Load on the cam/roller rockers? I'm sticking with a hydraulic roller cam.

[greenXpress]

Thanks for asking......now I too will wait for an answer.

[Scott Liggett]

Some say that higher than stock ratios can put pressure on the valve guides wearing them out faster. I can't see how .005 more will hurt anything in that respect.

Also, you will have to check to be sure the nose of the lifters are hitting the top of the valves correctly. Shorter push rods could be needed, but I don't see that happening.

[TC]

If you weren't changing the cam and just looking for a little more lift out of the cam that you have, I'd say go with the 1.65's..... But since your changing the cam and going to achieve your desired lift going that way I'd stick with the ratio the motor was designed to use...... It's not like the OEM's don't spend Millions of dollars in R&D to come up with less than optimal rocker arm ratios...... Go with the 1.6's you'll be fine.......

And as for advantages of running a shorter one over a longer one in the mechanical since, that could be debatable, but I don't think the gain would justify the expense of correcting the geometry that you have to do with running the longer rocker...... Though one thing I'm not sure of is how longer valves coming into play with all this...... But then maybe someone smart than I could chime in on that......

[realsteelfreak]

Your changing the cam anyways, I dont see a gain. on a SB chevy trying something different , yes it pays off just changing rockers.

[JeffMcKC]

I would use the higher ratio you can accelerate the valve quicker with ratio than ramp.

[TC]

I would use the higher ratio you can accelerate the valve quicker with ratio than ramp.

Do you need to up the spring pressure to compensate??

[JeffMcKC]

The spring is a matter of balance to have control. If it set up to control the mass at a higher speed but should be set up close to bind to help control it. The cam he picks wont be a real radical lobe if its like most Buicks it wont be needed.

[CDMBill]

I like the increased rocker ratio idea, but like everything the related question is whether they will require other mods or parts to work properly with correct geometry and valve control. Will you be changing springs, going to light weight retainers? Buick specific knowledge comes into play here.