Well, I've got the back of the car (1500 Midget) up on jack stands trying to
track the clunking noise.
Adrian, check the tolerance at the crank. Sounds like your thrust washers are
ready to fall out. Pry against the crank pulley pushing the crank to the rear
of the car. Have an assistant depress the clutch pedal as you watch the crank.
If you can see it move (and you probably will) the washers need to be replaced.
1975 Midget - some day auto-x-er
1973 TR-6 - no longer leaking gas into the trunk!