Is the engagement point on the clutch adjustable? The friction point on son's 4000 is about an inch off the floorboard. If it's not adjustable is this a sign of needing a new slave cylinder?

Just a plain jane 4000?
Not sure what they use for a clutch system. If it's hydraulic, then there really isn't any adjustment. There is a slight amount of adjustment at the pedal end to fine tune a master cylinder install, but it's not much. Look for wetness at either cylinder indicating a leak. You can try bleeding the system, as it might have some air in it which would cause this. If that doesn't fix it, then the clutch itself may be ready for replacement (though they usually last a very long time in these cars).

It's an 85 4000q

PO said clutch was replaced so I suspect you're right.

Thanks for the help!