Stiffer clutch springs

[Bajaman]

Does anyone know if there is a clutch with stiffer springs available? It is very easy to get my 4spd stick wagon into an oscillatory bucking mode. For example, if I abruptly let up on the go peddle and then get back on it, the car will buck violently until I dampen it by letting off the go peddle again. This seems like the stiffness of the springs ( or perhaps I have a broken spring) in the clutch may be one of the culprits. Any other slop in the drive train is also obviously not going to help this situation. All the driveline rubber is new, diff seems tight. Thoughts?