Rallye Dash Swap

OK, I have a Rallye Dash from a 67 Barracuda that I would like to install ijn my 72 Scapm. I have heard that this swap works if you have the dash frame as well as the instrument cluster. BUT....I dont know anyone that has actually don this swap. I would appreciate input from anyone who has done this type of swap. I am concerned about the mateing the wiring harness with the current harness at the firewall. Any other issues I need to be aware of?
Thanks in advance for your help