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What can I expect if I change from 1.5 ratio rocker arms to 1.6 ratio rocker arms on a SBC engine? I have a very mild cam in this engine so interference shouldn't be a problem. Will this affect performance? mileage? I understand it might give a little more lift to the valves?
Lift will increase by the same amount of the increase of the ratio. Be wary though, it can change the geometry of the rocker tip to valve tip relationship. This creates a different load and causes premature guide wear.
Here's an example of an ideal tip position that you should achieve. Some 1.6 rockers can tend to place themselves at a different contact from the original 1.5 position and instead of keeping a good centerline axis, it it increases the degree of inward sweep changing the tip arc not true to the valve centerline. Some manufacturers always pushed the pushrod closer to the fulcrum and this does tend to create an extra load on the rod and clearancing in the pushrod guide area will have to be accomodated.
It will increase your valve lift by about 7%. On a mild engine, I'm not sure you could feel the performance increase in the seat of your pants.
i am not to big on this i must be missing the boat?? going from 1.5 to 1.6 i do not think it is worth the added trouble you get in to. every one ,s rocker geomerty is different from harland to crane so you need to get the right length push rods i use to tool that checks this at mild lift..i would think see more from a re cam