AC box change from regular heater box 67 barracuda

I have got a 68 AC barracuda heater box and hoses I want to use in my 67 barracuda. As far as the controls, I have Chrysler 300 dash I am putting in the car that has what appears to be the same controls that were on AC dash I had for a barracuda (barracuda dash was in poor shape - parts only) Has anyone done an AC conversion? From what I found so far, I need to make bigger hole for the blower motor and additional hole for the AC lines. Let me know if this is fairly easy if you have done in past or if I am tackling a major job and what I might be missing please. I am trying to make a driver that I could use on many trips and AC would be very nice addition.

Thank you in advance for any assistance and information you may be able to lend.