505 stroker fresh off the dyno - Power seems low? Thoughs?

Then therein lies the issue. He's built a 505. That's a 4.15 stroke engine. That 5060 is for a 4.250 stroke and has a MUCH shorter compression distance. He probably has 7:1 compression with his combination.
4.350 bore 4.25 stroke comes up 505. The 5060 is correct