[HO455]

Part two of rant. I didn't use the big gasket in the set but I will point a problem I noticed to others. This gasket is larger than the box it is shipped in so the manufacturer folds it up. As a result the foam is crushed and it doesn't recover its original shape when unfolded. (See photos 1&2.)

I forgot to include that I used window seal cord from a box store to seal the fiberglass heater box to the metal parts of the box and the firewall. (Photo #3) Others here had posted they have used it without issue. I would have liked it better if it had been slightly larger in diameter. It just seemed to be some what undersized even though I did see one spot where it excess pushed out I'm not confident it sealed completely. I used the window seal it as it was only $7 as compared to the correct 3M sealant which was $46
at NAPA.

https://www.napaonline.com/en/p/MMM08578

This seal cord goes in the groove around the flange on the fiberglass heater box. In the 4th photo you can see the ends of it sticking out (Green arrows.) from under the gray plate over the blower fan. The yellow arrows point to the groove around the rest of the heater box where the seal cord needs to be installed. I believe this is to prevent air leaks between the engine compartment and inside the heater box. The red line in the last photo is a rough approximation of the areas the seal cord goes.