I am working on a 1989 SBC350 TBI. The previous owner I purchased it from had replaced the factory top-hat style throttle body intake air box with a K&N "cold air intake" (a sub-par cone filter on a stick, really). I would like to convert it back, however, I'd also prefer to option one of the enclosed airboxes that some 1989-1991 K5s and later GMT400 Tahoes and Yukons were equipped with. It should resemble the following: 1989 k5 blazer engine bay - Search Images

However, I cannot seem to find a part number - just replacement air filters. Does anyone have a part number?

 

I may have answered my own question; its two parts:

"Cleaner A" 25087956 / 25097769, and

"Air cleaner intake duct (rear intake tube)" GM 15602322.

Revised Question: aside from pick'n pull/auto yards, does anyone know where these parts can be sourced? Chevyparts/partsgeek list them as "discontinued", without purchasing options.

 

Yeah, the picknpull yards will be your only source. Good luck and best wishes.