Clutch Adjustment

[Sweet T]

The clutch pedal in my 69 has for as long as I've know the car sat really close to the floor.  I would say there would be no more that 2 inches movement before it hits the floor.  The clutch has very low miles on it from what I understand.  Does the adjustment under the floor dictate where the pedal will sit.  The car is slipping a bit in third and fourth.  I think the plates might be contaminated with oil but wanted to know if this adjustment would bring the pedal up/ reduce slippage ect.  Right now there is very little freeplay before the clutch starts to make contact.