I have a 96 Mitsubishi L300 Versa Van and had the cylinder head refaced, changed valve guides and installed new intake and exhaust valves. After completing the installation, the engine has no compression at all. This engine, model 4G63, has a hydraulic lash on its valve train, hence, no adjustment is necessary. Loosening the bolts on the camshaft cap made the engine run. My question is, what is the minimum or maximum thickness that I can take off from the head to make this hydraulic valve train works. I am using a Chilton Repair Manuals but it only provide me with some technical specifications but not the cylinder head minimum or maximum warpage tolerance. Kindly provide me with some of your expert advice. Many thanks in advance. Louie 

Check the block top surface for warpage, and make sure that the surface is free from gasket chips and other foreign matter:
Standard Value: 0.05 mm (0.0020 in.) or less
Limit: 0.1 mm (0.0040 in.)

If the distortion is excessive. correct within the allowable limit or replace:
Grinding Limit: 0.2 mm (0.008 in)
The total thickness of the stock allowed to be removed from cylinder block and mating cylinder head 0.2 mm at maximum.
Cylinder block height (when new): 284 mm (11.18 in)

I hope tht was the information you were looking for. If you need more, please let me know.
Good luck!