I just posted in my thread as well, but I don't think that's even possible with the brackets they include in the kit. I had a similar issue where my passenger side brackets seem to line up okay and position things relatively well, but the driver's side bracket are way short. In my case it's ~2" short, so they hardly even reach across the opening in the core support to be able to bolt to anything, let alone pre-existing holes. I also seem to have a much different passthrough hole in my core support for the hardlines as I just have a ~1.5" diameter hole or something like that compared to the nice big square opening shown in the pictures here. It's going to be tight for mine, but it looks like they will just fit.
@GoldSwinger71, how did your box fit on the firewall? I mocked up the lines today to see what orientation of fittings I'm going to need and suffice to say I hope I never have a problem with my #8 coil pack or spark plugs as I'm not sure if I'm ever going to be able to change them again without pulling the A/C line every time.