Richard gets 350 hp out of a stock 5.9l longblock with 4bbl headers and a 212 cam, I would say the 5.2l would get similar. The 380hp crate engine gets 400 hp with 230 cam so your cam is about in between so I'd say should maybe get the 375 hp.
The 5.2l is gonna need about 500-600 more rpm and higher stall and about a half a ratio deeper gear to perform similar as a 5.9l. So that's up to you if that's fine.
Here's a basically 400 hp 5.2l (318 with magnum heads)
It is worth mentioning the 280h cam selected for the 318 build will be a dog on the bottom end if you don't follow the rest of the build and the compression up.
Years ago we used that in a 350 chebbie with stock low compression pistons and a stock converter in an 81 pontiac grand prix with 373 gears. Dead off the line. My 360 with much less cam and equally shitty compression destroyed it drag racing in route 8.
Something arrund the comp 262h probably would have been better for our application.
And the 350 has the advantage of cubes.