Pretty sure M.B.Doc or Gilly will know.
A264172
What it means is this, I'll just use a Chevy for this.
One end of the rocker arm is moved by a pushrod, which in turn is actuated by a hydraulic lifter, which is actuated by a lobe on the camshaft.
The other end of the rocker arm actuates the valve.
This is not a 1:1 ratio.
For instance on a small block Chevrolet, this ratio would be 1 : 1.50.
I.e. for every 0.100" lift at the camshaft, you would have 0.150" of lift at the valve.
For more detailed information ( or if you really care ), you'll have to pay me.
