inline 6 250 std rocker arms question

[Husein-p]

hi
i have a problem with some info about comp cams specs for l6 cam

factory std rocker arms have 1.5 to 1 ratio ok ? but for example if i choose 61-233-4 part# with this cam we have 0.28 for lobe lift but for valve lift we must to have 0.42 but in comp cams specs said 0.489 !!!

why ?

i checked cam specs for v8 sbc like 12-105-3 muscle 929H cam
comp cams said 0.26 for cam lift but for valve lift said 0.39
this is true because 1.5x0.26=0.39

but for l6 0.28x1.5=0.42 if 1.75x0.28=0.490

chevy l6 250 std have rocker arms with 1.5 ratio or 1.75 ?!!!!
or comp cams specs calculate with 1.75 ratio ?

tnx