Antiburn has a point - the old 7s are notorius for vacuum actuator failures (in dash for heat/AC vents) the parts are damn near impossible to find (even new @ dealers) and is labor intense something like 6+ hours to disassemble dash just to get to them. Plus there has to be a
1/2 mile of vac lines in the dash.
When they run, they are great. But when they "burp" - get out your checkbook. If you get one, hoard about 5 more for parts.