Should I reuse Suburban NT-22 case? Replaced with NT-30

[Jesse Lee]

Good Morn Airstreamers of the world.

I decided to swap out the NT-22 from my 1973 Argosy with a new NT-30 because of the recall part and an ailing pilot light. I have read a ton on the forum to best educate myself, but i am still left with questions in this installation process:

1. Is it recommended to reuse the NT-22 case in conjunction with the total NT-30 case?

2. What are the pros and cons to not reusing that old case?

In my mind it makes simple sense to just go all new with the NT-30, meaning not reusing any parts or shell of the NT-22. I went that direction by adding a new base with plywood and it aligned and connected perfectly with my outside vent holes. (see photos) Am I heading in the wrong direction with this? Is it ok to just go with the NT-30 and no outer shell from the NT-22? I would love to lighten that furnace any way i can, and that old NT-22 shell is super heavy. But, from what i am seeing, more folks are going with installing this unit, inside the old NT-22.Would like like your help in this matter. Thanks a ton in advance.

[Argosy Heir]

Jess, you are on the right track. I used nothing of the old furnace during my Argosy renovation. I think using the old furnace case is a function of the Airstreams metal ducting system. At least in my Argosy , the ducting is done through flexible HVAC hose and it appears that yours is also.