Is this possible first of I talked to a gentle man from AutoZone and he said there was quite a few things I needed to do in order for it to run in my car

 

Depends what you started with (V6, V8 - 305, 350, TBI, TPI???)... and what you want to end up with (carb, fuel injection). No problem physically putting it in, but what it needs to interface with will be the problem.

 

Right now I'm running the 305 and I plan on keeping tbi for now

 

You mean you want to use your 305's TBI setup on the 400?