I did a lot of rocker arm testing on the dyno with my 470 low deck. We ran multiple dyno tests using multiple rocker arms and multiple rocker arm ratios. Basically a big zero difference. I think I spent around $5000 testing rocker arms and didn't find any power. Pushrod length was critical even with shaft mounted rockers. We never saw the need to move the shaft up or down with any of the high quality rocker arm systems. It is common to have to shim and/or machine the stands to move the rocker arms sideways for correct alignment.
https://www.motortrend.com/how-to/trying-find-extra-power-rocker-arm-testing/ As someone who's spent hundreds upon hundreds in custom pushrods I probably will never use again, pushrod length is not unimportant, but there are more important things to consider
