bigger is better when it comes to engines (as long as cost is reasonable).
A 454 cost the same to rebuild as a 396. Building a 396 instead of a 454 is like building a 283 instead of a 350, makes no sense on a performance per dollar stand point.
I rebuilt my 396 because I was bored and had the engine sitting under my work bench. I wish I would had left it there and did another 454, or 496, or at least put a 454 crank in the 396 block and made a 440.
When you build your engine make sure everything matches. compression ratio, cam, gear, stall converter, and intake.
A 3.08 gear and stock converter will require low compression (8 to 9:1) and a mild cam (206 to 218 at 0.050") and a dual plane intake. If you plan to run more gear and stall then the engine can have more compression and cam.
what gear and stall do you plan to use?
A 454 with flat tops can work with those 802 heads with a mild cam. So just install a 454 block with a mild cam under all the 396 stuff. But use the 454 balancer and flexplate.