New engine 15-1 pumps 180 when 200 water temp/180 oil temp. Pumps 225 when 140 water 140 oil. Hr run time with 6 pulls on transbrake. Block filled to bottom of water pump holes. 355 sbc. Honed with plates. Thoughts?

may not be broke in yet,it has been common for my stuff to loose numbers when hot,if memmory serves around 20

I'd do a leak down test cold and hot and try to figure out where you're loosing (leaking) cylinder pressure......
Usually when it's heat related it's the cylinder walls moving/going out of round.

^^^^. My bbc stocker bores always move with block fill even with heat cycles. Re honed with plates and it was fine. Loss was 8-10%. Not round.

Perhaps some of it is just physics. The air in the cylinders wil certainly be hotter with an engine at full temp. Hot air much less dense, mechanically compress less dense air and you get a lower psi.

^^^^ hmmmm