The considerable angle of the LS, LT, and LT4 intakes can cause issues routing inlet plumbing and clearance to aftermarket accessory brackets. One option is to mount the throttle body upside-down, BUT this changes the air flow to the intake and can cause poor cylinder distribution and drivability issues.

The 717-15 levels the throttle body for these swap applications without changing the flow the GM design intended. Other four-bolt intakes with routing issues can also benefit from this adapter.
Low RPM correct Low RPM with throttle body upside-down

LT car intake blade orientation shown above. Other LS and LT are reversed but the same effect applies.

Benefits:
Maintains proper throttle body blade orientation.
Eliminates drivability issues associated with inverting the throttle body
Allows clearance to aftermarket accessory brackets
No harness rerouting or extending required
Allows use of cable operated & other throttle bodies on Gen-V 5.3L Intakes

Intake applications:
Works with both truck and car LT intake bolt patterns
Works with all 4-bolt LS intake bolt patterns

Throttle body applications:
Works with up to 95mm intakes and throttle body openings. Does not work with larger openings.
Works with common LS and LT 104 x 70mm bolt pattern throttle bodies.
Will not work with 98 x 70mm LT truck throttle bodies.
Adapts LT 5.3L Truck intakes to Common LS 104 x 70mm Bolt Pattern - fits most LS & LT Throttle Bodies.
Works with Holley 92/95mm Hi-Ram and Mid-Ram intakes.