Sounds like a cool project.Love the intake.However it probably won't perform well with that cam,low compression,and small c.i.
The carbs are a bit much on a stockish 400 but can be made to work.Probably not going to have a lot of bottom end.Plan on some gears.
Nothing wrong with the heads.As suggested I would mill them accordingly and try to get your compression up to 9.0-1 or 9.5-1 would be even better.
BTW the cast crank will be fine for what you are doing.Buy a weighted flexplate and spend the money elsewhere.
1 7/8 headers are a tad big for a street driven 400(1 3/4 would be better for low end and mid range).That being said they will work.
I would pick a different cam for that motor.Need to know the rest of the drivetrain(stall,gear,weight of car) and intended usage(street,street/strip) to pick one that will work.