Not a waste of money at all. I run a low deck 512 in my B body car. It has ported Edelbrock heads and HP cast iron manifolds. The trick is getting the right cam ground for the engine. You don't want a lot of overlap with the manifolds.

Another thing to consider is going with EFI. EFI also works great with less overlap so the two work well together. You can build a really smooth quiet engine that will pull like a freight train. Make it 500 inches with ported aluminum heads, cast iron manifolds and EFI.