360 magnum into abody and efi/carby questions

Hi all
I am looking at installing a 360 magnum into my Abody. I already have a magnum in my other Abody car and its supercharged with a carby and goes great. So this car I am doing now will not be a super powerful car. I want it for more of a tough cruiser with over 300hp to 360 FWHP and keep the aircon etc.

As it will be more of a cruiser I am contemplating keeping the factory efi. I have done some research on this site and it looks like I can keep it efi and swap it as long as I have the factory ecu and buy a new wiring harness, efi pump and regulator.
Have I forgotten anything? Do I need anything else?

If this is all I need to do the next question is will the factory efi be ok to up the power a bit or is there a low limit I can go. The 1st magnum I ever built was 360 FWHP and all I did was swap the efi to carby, install extractors and changed to this cam. I would be very happy to have this as my cruiser but I don't know if the factory efi will allow this.
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=661&sb=0
I do have 2 of these cams. One with lobes ground at 110 for a carby and one ground at 114 for efi so I can go either way. My concern is that I spend the money keeping the factory efi but end up not being able to get my required HP because of the efi may have limitations.
Any help is appreciated.
cheers