440 what am I missing here?

By your description, sounds like a converter swap would be the first logical step.

I don’t know what kind of tuning capacity the FiTech has, but as Andy mentioned, something like the Sniper set up with the EFI controlling the timing would really help with the response.
Whether or not that same type of situation is available with the FiTech or not...... I don’t know.

Try the converter first...... and if that doesn’t get you all the way there, look into having more control of the engine tuning.