For an intake, look for an Edelbrock Performer, but not the RPM. It's better for bottom end torque. I would go with either a 500 to 600 cfm 4 bbl or a Q-jet that has been rebuilt by someone who specializes in them. The q-jet will get you the best fuel milage, and it's primaries are sized for good milage.
The heat riser closes of the exhaust for that side, and routes it through the intake under the carb and out the other side. Helps with running a cold engine.
Dual exhaust with 2" pipes will be plenty for the 283. If you go bigger you start scrificing low end torque, which is what gets the truck moving.
