Help needed for my project car

:welcome: from :canada:
Lots of great people here with tremendous knowledge and experience, but I think you should start a build thread for your Barracuda first.
You will find that it will be much easier for others to help you get answers if the questions are more specific.
Photos of your car and the areas you have questions about will help as well. We all have ideas and thoughts on how we might do things, but your ideas may be vastly different.
Dropping a big block into a 66 Barracuda is not a simple task but it is very doable, no doubt that someone on this site has been through it and can help you avoid some problems.