Judder when pulling away can be caused by contamination of the clutch friction plate or front to back alignment of the engine and gearbox assembly. I had a DOHC which juddered terribly after I re-fitted the engine and box. The tail of the gearbox was about 20 mm off to one side. Took ages to spot what it was. I loosened the engine & gearbox mounts, straightened it up, re-tightened the mounts and it was fine after that.