You can get to quite a bit of vacuum stuff just by dropping the kick panels above the footwells and removing the glove box. Test everything you can get to. I see a dash pull/repair/replace coming up in my near future in the '81. It has a blue interior and the dash is cracked all to heck and back. I believe I am going to install the black dash instead of a blue one. Black seems to hold up better. In addition, the climate control system does not work as it is supposed to and I will have to sort that stuff out. I'll probably start on it in the spring (around February
).