The specs I have located for the 190e 8valve engine are minimal cylinder head height 97.8mm, mininum block height 292.35 mm. The question I have is if the head is a smidgeon thin, say .o8 mm (97.72mm), and the block height is at minimal thickness, how can I tell what the clearance with the pistons will be? If enough? If I assemble without a head gasket and no tapping occurs will that be good enough? I am aware that I may need an offset key for the cam.

I saw a photo in an engine rebuild book that had the mechanic place putty, (play-dough?), in the valve contact area and then put the head on with no gasket. Turning the engine over slowly by hand would show imprints in the putty if there was no clearance.

When I ran the 8V engine in my race car I would have the head cut .025" below min specs & only above 7500 rpm did the valves come in contact with pistons. So you should be just fine. Of course you will need preminum fuel unless the engine is from a 84 to 86 car.