I'd be looking for "around" 540hp/560tq, based off what I've seen from similarly built 446's, and adjusting for the added cubes.

I was talking to a friend of mine while we were dynoing a 505 he built for a customer about how there can be a fairly noticeable difference in what the dyno sheet says depending on where you go.........for a host of different reasons.

He reminded me of a 2bbl circle track motor he had years ago that he had tested, completely unchanged, at 3 different shops.
The high to low spread was about 30hp......on a motor that barely made 300hp.

It was something like 285/300/315.

Edit- I see you'll be running an elec water pump..... So add a few for that.