Turbo for mild 408?

So...I happen to have a spare 408 lying around. And, I happen to have a spare b body lying around that needs a small block. I happened to be daydreaming about putting a turbo on said 408. I happened to see some popular videos on YouTube regarding cheap eBay gt45's making up to 800hp, and it got me to thinking about what turbo might work for my 408 in a b body?

Seriously though the question I'm getting at, is, would a gt45 be ok for a low rpm mild 408 or should I step up to a larger unit? Would back pressure be a problem if I kept it under 5500?