Advice: Solid Roller or Hydraulic Roller for street car
With the right cam and those heads you could easily get in the 500 hp range. Everyone here is gonna have their own opinions. The good thing is most of these are correct answers. There's a lot of ways to build a street ripper. And the factory sbm short block in good running order can take that all day long just stay out of detonation.
Think about the LS crowd. Lots of 5.3 screamers out there with good heads making north of 500hp. Most of those guys will be running a hydraulic roller. Same recipes apply to the 318. The trickflows are damn good ootb and can get you there with your 5.2. One thing I don't know is would you run into valve clearance issues with the larger valves on the small bore. Others here can answer that.
The other factor you will have to think about is available piston to valve clearance with the short block you've got.
If it were me and my money, it would be a solid roller with street oriented lobe profiles. That's the direction I'm going with my build. If there were good retrofit hyd roller lifters out there it wouldn't be so cut and dry, but I've seen a lot of issues with those lifters and would worry about that route.