400 Build vs 440 Build

I've got a 400 with the 440 Source 499 kit and love it.
As a cautionary tale keep in mind the increased stroke and bore will cause a high comp ratio without any other changes.
Get the dished pistons and even with closed chamber heads you will be OK, just food for thought if pump gas is your goal.

I did have a 440 in the car 1st and was happy for the little extra room with the 400 block.