I agree with FAI17. Quoting 347 on std heads was misleading after playsatan was offering figure estimates for a VF28 on std heads.
To the OP, my RA engine which came from a P1 running a VF28, std 440 injectors and sti 6 TMIC and exhaust was running 312hp. As playsatan was eluding to, the non-sti heads could be the limiting factor on achieving more than 320ish on your setup.
Is there a specific reason you are going FMIC? If I were you, I would be looking for a more efficient TMIC than the std one. The STI 6 or later will not hinder your figures running a VF28 but will give much better turbo response. I ran a FMIC and 18G for a while and found the lag too much, to the point where I ditched both infavour of a VF35 and STI 8 TMIC, its like night and day.
Just sharing my findings and opinions.