RV Repair: dash ac lowside port, side ports, happy camping

Question
I have a 27ft 1985 allegro motorhome class a, I'm.  Trying to service the ac and can't find.  The low and high side ports. All lines go into a box on the passenger side. The looks like it houses the heater core. Can you help

Answer
we just had one of these in the shop.
i believe you have a big block chevy.
trace the lines from the heater box back the engine.
you should find the a/ac ports its going to look like a tire valve since it came with R12
they should have the ports under the front access area but they may be under the inside engine cover
thanks and happy camping don