my 79 c20 350 with sm465 clutch was going out i thought- it was slipping pretty bad but then yesterday when i was drving i put my foot on the back side of the clutch pedal and lifted towards me- the clutch was not getting fully engaged. so now i can start off and as soon as i let the clutch out if i lift up it will fully engage and work fiine- is there any adjustment on this so it engages itsself completely or???