This for the 77-79 Pontiac Trans Am with the Real Pontiac 400 V8 ..its the underside of the fibreglass shaker.

It clamps onto the top ring of the specific air filter housing.  You would buy this if replacing the lid ..OR changing from another engine brand back to a Pontiac....

Pontiac is different to Olds or Chev SB in this shaker base plate due to offsets and extended depths of underside wall support that positions the fibreglass shaker to a central position.. so you can .

• 1: Close the bonnet properly
• 2: Not have the shaker offset or too low.

This is for a Pontiac V8.. ie 400/ or so equipped 350/ 455 engine.. but is build right for the 77-79 Trans Am.