Anyone make the plenum air inlet or is it custom time.

It's custom time!     Make a block of wood that fits around it in 2 halfs.. get some sheet steel and... a hammer!!  😉

Fawlty Towers - Hammer Sandwich - YouTube

Edited October 11, 20213 yr by dutchzcarguy

Or you could contact one of the better panel fabricators.  They could probably supply one

I've seen another discussion about this piece in recent months...I wish I could remember where so I could point you to it to see what that person did.