400 engine Help Needed

Need Advice.

I have a very low mileage 400 with 8.5 compression that makes very little power.

I don’t want to spend a bunch of money building the motor or stroking it since it in a nice street car. Ideally if I can find 400hp I would be happy.

I’m looking for ideas to bump up the compression and make more power. (Deck the heads? Buy after market heads? What do you recommend?)

I’m also looking for advice on a cam and intake for this combination.

It also in a heavy b-body