1980s 318 questions

The 80’s motor mounts are different from the earlier years. You’ll need to have the motor mounts rod your year car.

The flexplate on the rear of the engine that couples to the torque converter if stock will bolt up to a converter IF the converter has the provisions for the bolt size. Ask the seller if it is OE flexplate compatible. Stock or mild upgraded torque converters are often compatible but not always.
The intake (RPM and most every other intake) will not cover a semi circle area on the head. Do not be alarmed as this is a heat sink designed to be there. Even factory intakes do not cover this upside down moon shaped hole in the middle of the head/intake area.
All other emission devices can be ignored, or lugged, removed although I recommend the PCV valve and a breather be used for good running engine service.