1.6 Rocker Arm Performance Gains over 1.5 Rocker Arms
I think simple ROT is if you're undercammed it will likely make more power, if you're not, it probably won't...
if you had a cam like this one:
More Information for MELLING SPD22 or even this one
https://www.rockauto.com/en/moreinfo.php?pk=10211292&cc=1435034&pt=5260&jsn=541 you might make more power going from stock rocker to 1.6 roller rockers.
Here’s the thing, while you are potentially right, actual gains may not translate into anything meaningful.
A lot has to do with how well the cylinder head flows. On a stock head where we will say good flow lifts fall after .500, exceeding that lift doesn’t help as much as you will hope it does. The more lift past the stall or point of flow rate tanking will not add anything worthwhile.
If the cylinder head can support the flow of the higher lift, the gains become more better and possibly worth talking about.
The other half is the duration of the cam. A quick blip valve opening of a small cam is vastly different than a longer duration cam.
At 209 or 224 intake duration, the gains seen between those two cams could be a notable gain but will be a laughing stock in a comparison of a cam with 255/260 and better duration but still may not be what you think.
The faster action of the valve movement is a nice plus but as above….
The last thing is, this is all engine dependent. Every last aspect of it.