sh_t ton of advice and help needed

[JIMBATTLECAT]

MY name is Jim and I'm a car guy i have 1964 for galaxy 500 with the 390 Thunderbird, a 1976 Cadillac eldorado convertible a 1985 corvette and a 1986 Mercedes Benz 560sl all were or are fixer uppers , now i have a 1980 928 and could use some advise and some parts access. Porsche paint in the dark is brown and in the sun is maroon.
On another note the Porsche i have has very little vacuum at the vacuum advance and compression is 180 across the board except for number 5 which is 120 number 3 runs rich and i under stand the firing order to be 1-3-7-2-6-5-4-8 the car sat since 2012 i drained and cleaned the tank i added a little marvel mystery oil and trans fluid to the crank case ran her just to get her warm then changed the oil to rotella 15w 40 and added B&G oil treatment and B&G FUEL TREATMENT with 20 gallons of ethanol free 93. idles poorly in my opinion but will rev up to 6000 at the drop of a hat. I'm hoping that the low compression on number 5 is just a crudied up valve. Sorry for dropping so much at once I'm here to learn

[Danglerb]

Fenders are Euro, if the whole car is then the engine could be S or not S, but CIS injection either way. Idle is often from both old dirty injectors that need to be removed and cleaned or replaced and a bunch of vacuum leaks in the intake. CIS is very sensitive to crud in the fuel, and/or sitting for any longer time. Usually that means rebuilding the WUR (warm up regulator) and fuel distributor. To play with CIS you will need a set of CIS fuel pressure gauges.

More picts and if you don't mind the vin and/or motor ID (stamped into a flat spot directly below the hose feeding the radiator).