I was watching engine masters and saw this test and saw this https://youtu.be/TvQHgt-tF7Y The two alu rockers were different ratios and produced diff results so how do you know what the correct ratio is for your A series. Just by the way there was also this https://youtu.be/8VjFZMKvEwY How does the rocker ratio and cam /cam lift etc work together? I see yellaterra also has diff ratio's

A 1.5:1 rocker will move a valve 1.5 times the lift of the cam. A 1.6:1 rocker / 1.6 times which equates to roughly a 5 to 6% increase in valve lift thus gaining a few extra hp. Dont think it affects duration but do put less load on the valve and add to longevity / friction.. Worth it ?? Just depends on engine setup and how you value your motor. A-series have a pretty tough rocker from factory. I am using them which needed a higher tower. My motor is not fully assembled yet so no testing too.

So if i understand you,you also using roller rockers.If i may ask where did you get them cos i see there is quite a few places that sell them.

Check this out a DIY head job making 92hp more than std. Extra large intake by making changes to the head ---How they change the pushrods then? https://youtu.be/aijyLKCvbU8

I run rollers
I get alot more lift from them as I run 1.65 ratio
However... the rocker is heavier... so I don't rev it as hard and try to keep my redline around 7600
People with std rockers can run higher rpm... but I get alot more valve lift and airflow than most

Mine are yella terra
Don't think you can get them anymore unless special order