Need help with injector size with friends procharged car

This is concerning my friends procharged 01 cobra. He putting a 18 pound pulley on his car tomorrow. Right now he is running 10 pounds of boost and his 42 lb injectors are maxed out. Hes putting 510 rwhp right. With a A/F of 12 to 1. I know he needs a tune. Hows his a/f ratio gonna be with that small pulley on there. Its a completely built 4 valve car, stage 3 heads, sean hyland blower cams, manley i beam rods, etc, etc

What size injectors does he need. Hes already got a 1200hp aeromotive fuel system and hes running a FAST SpeedPro.

Any advice is appreciated.

Thanks
Josh

thanks yall

Josh