Edelbrock Performer Carb question

I am contemplating a new Performer carb. 68 Valiant Stock 360(mild cam so I was told but I don't think so ). Stock intake,Doug's headers. I don't see this thing ever going above 5000RPM.
With that in mind would I be better off with a 500 or 600 CFM carb. Just want to cruise it to work and local car events.

Either would work just fine.
I run a 600 and a dual plane intake on my 5.9 magnum and it's pretty much flawless, but obviously it would have more wide open power with a bigger carb but like yours mine is a daily driver and I don't need to squeeze everything I can out of it.