David,
My little 347 that I did made 482hp @6500 and 430lb-ft with 10.3:1. The restriction was that the customer couldn't afford a new carb at the time, so we ended up using an old Demon 650 that he had. It wasn't a max effort as he didn't need that much horsepower to run the class he had, but he thought that at some point he would want to run a faster class. I used out of the box AFR 185cc heads and a Super Victor intake. It was a nice little motor.
If you don't have a cam yet, I can help you pick lobes. I rarely order off the shelf cams. But based on where you want the power to be and how often you want to do maintenance, I can help out.
There are some good lobes that make real good power, but they're harder on springs. I like the TK lobes for a solid roller, but they're pretty radical. However, if you want to make the power, they do a good job.
If you're planning on going a little wilder on the cam, I would go with a billet cam and up the spring pressure. If you think you have room, you can shim the spring up a little more, as long as you have good retainer/valve seal clearance and coil bind clearance.
Also, sometimes valve lift will fool you. You may have good piston/valve clearance with this cam, but a larger cam with different valve events may hold the valve open longer in a certain spot and it may get close.
When I assemble, I clay the piston up just to check radial clearances. For depth clearances, I use a dial indicator with checking springs and check it every 5 degrees.