New 408 build finally started

I was looking at this a little more in the last picture of post 252. Your rockers are mounted on the shafts in their approximate positions. You are holding the pushrod against the intake port to left, I assume. The adjuster appears to be just to the left side edge of where that pushrod diameter is, and it kind of looks like a 5/16" pushrod. So half of the assumed pushrod diameter is around .156" or so. Add that to your .350 offset so far and you would be about .506" and still making contact with the port.
A couple guys mentioned W2 rockers. Harland Sharp's website lists W2/W5 intake rocker offset as .775" according their applications. So stick .425" worth of feeler gauges between the intake rocker and mounting pedestal, just to measure the movement of the pushrod adjuster and pushrod, not worrying about the roller tip at all, and see if the pushrod clears the port. You can practically hold a set of calipers up to that picture and see how much it will take to get the adjuster into that pushrod cup. But then there is no guess work.