Is there any kind of adapter that can be bought to install a 3rd gen fuel injection set up to a 12a mild ported engine and is this idea not logical. I am not sure if it could be done or not. Thanks in advance for what ever advise you guys can give me.

 

Possible.. yes
Practical absolutely not.

If you want fuel injection on your 12a there are several options for all of the hardware needed. Throttle body(s), manifold, and a stand alone ecu are the essentials but many other pieces will be needed and all of them will be based upon your choices for those first three.