Holy jeeze. The pump? I would be more worried about the lines. If I was building something that wild, I would start investing in a Aeromotive fuel system. But I'm going to take a wild guess and say your stock lines CAN NOT keep with the fuel requirements of that. If you weren't planning on the big shot of nitrous, and keeping it N/A, I think stock lines and a 255 would be fine.
The motor will be in the car for a year before the nitrous system goes in. I'll do the 255 in tank pump and then upgrade the fuel lines before the nitrous goes in. Thanks.
I'm doin the same thing for to my car. Right now I have a 255LPH pump with 1/2" feed line and 3/8" return. Once I put the nitrous on though, I'm gonna be switching to two external 255lph pumps. The single 255lph will be enough for the N/A power, but won't be able to handle much nitrous.
My approach might be to install a boost-a-pump that is activated off of the same window switch as the nitrous. A 255L high pressure pump at 40 psi and 17 volts is roughly 322 liters per hour.
I'm no nitrous expert but I'd also be running a wet system with its own fuel lines reaching all the way back to the fuel tank and/or sump.
This would solve a couple of problems:
Stock fuel system and rails require no upgrade (both will support 500 FWHP and Torque)
You won't have to run HUGE fuel injectors (42s will be more than enough for 450 N/A)
A secondary in-line pump can be slaved into the N20 nozzle fuel line if necessary
Secondary fuel pump can also be window switch activated so that fuel is not unnecessarily heated