Fuel injection.
 

I'm building a 350 for my '94 K1500 and was wondering if I should go with the vortec spider injection with the multiport upgrade or the atomic efi system with an Edelbrock air gap intake. I'm not going for anything really extreme, just above stock horse power and torque and maximising fuel mileage because I have to drive this truck for work.
Thanks for your help.

Since you have a 1994, you have OBD I which might not work with your proposed modifications. The main issue is that you have a pickup, not a car, so no matter what, chances are that you wont exceed more then 15-16 MPG on the highway with any 1994 pickup truck or even a newer one with the vortec spider fuel injection, With a
K-1500 4WD you must expect that. I should know, as my newer 1998 K-1500 with a Vortec engine will only achieve 16 MPG on the highway, if I drive it conservatively.

I'm aiming for around those numbers. I average about 12. I thought about building a mild turbo engine but the estimated cost was around 6k. But which injection system is better?

I am not familiar with the atomic efi system with an Edelbrock air gap intake.to make a suggestion. The spider Vortec does have better power and gas mileage then'the GM throttle body fuel injection system (TBI) however.