Rocker Arm Geometry Question

[Poulsbo]

Hopefully this is an easy question for you seasoned engine builders.
I’m in the process of setting up my rocker arm geometry on a small block 350 for my 65 C10 project.

I am using a stamped steel roller tip rocker from Summit (Picture) with a hyd. flat tappet lifter. AND, I am NOT using a light checking spring. (I bought the heads assembled)

I am also using a Comp Cam adjustable pushrod and the Pro Tool pushrod length checker tool (Picture) to measure pushrod length.

With the Pro Tool jig level/flat on the valve stem, I’m getting a pushrod length of 7.75”. BUT…when I paint the valve stem with a marker, install the rocker—with ½ turn preload—then manually turn the engine over two or three times…the roller tip wear pattern is slightly toward the back of the valve stem. Based on my research this is supposed to mean the pushrod is too short. Correct?

My question is whether or not I need to factor in the compression of the lifter since there is no oil pressure?

In my simple inexperienced mind, I imagine that the spring tension may be compressing the lifter enough to shift the valve stem wear pattern slightly toward the back. But with oil pressure, the rocker pivot will be slightly higher which will shift the valve stem wear pattern to the center where it should be.
Am I thinking about this the right way? Or do I just need a slightly longer pushrod?

Thanks for any advice!