Hi Vernon, Was looking at your post. I just ordered a NT30sp for my 66 safari
I'm not taking out the cabinets to do this, but will likely hack out the plenum too.
What did you do about the extra vent?. I suppose I could run a round duct somewhere in the kitchen cabinet and pop a hole in a door face. Eventually I will tear out the cabinets on an interior remodel, but not this year.
I also ordered a bottom duct kit with gasket Part number 520009. I suspect this will need to be increased in length though. In looking, none of the replacements I've seen fit without raising the unit up a few inches.
Will post if I get into too much trouble