Injector size?
what are your power goals, or estimated power? I would say ~50# injectors, Racetronix 255 or 340 pump kits ....preferably the 340 with those 50# injectors. These should leave headroom.
https://ls1tech.com/forums/2638447-post1.html
based on 600hp Naturally aspirated (NA) it seems you would need 45# @43.5psi (52# @58psi); this is near the single 255 limit and I think the next closest injector is 48# or 50# @ 43.5psi, so at 58psi that is ~55#, a decent bit above a single 255 pump.
I suggest either running with a 48# injector and the 255 pump; OR to be safer and certain you have enough a 50# injector and a 340 pump or 2nd 255 pump "Y" in with the feed.
A double 255 pump kit is rather easy to do. Look at MightyMouse write up in the fuel section and many others.
My recommendation is a 50# injector (or next closest size larger) and an additional 255 pump or a single 340 pump.


