[Healeys] Pressure plate question

[Jerry Costanzo]

Healey group,

One of the members of our club owns a Healey that is mostly of  early 60s
vintage.  His original transmission was having problems so he bought a toyota
conversion kit.  But he used his old pressure plate, and had clutch slippage.
The original Healey clutch plate is 0.004 thicker than the Toyota conversion
clutch.  The pressure plate is a 10 inch and must not be putting enough
pressure on the clutch plate or it would not slip.  The bearing is not riding
on the pressure plate surface.

Can this old pressure plate really be that sensitive to only 4 thousand
difference?

Or did he somehow damage the springs when he pulled it out of the car?

The only suggestion I had for him after measuring everything was b buy a new
pressure plate.  I can see no other reason for the clutch to slip.    Any
other ideas??

Jerry