If it's any consolation I recently got a bit bored in the old garage and decided to fit a metro 1275 head to a 998 engine I have lying around. I assembled it with no head gasket and no valve clearances - it turned over with some room to spare.
I'm not sure but I think this engine has a metro camshaft in it as well.
Yeah there is only normally about 9.8mm of clearance from the top of the block if the head hasn't been skimmed. If the engine number indicates the engine is A+ then a metro cam is likely..
Also, correct me if I'm wrong; but you may also need to fettle away a tad from the top of the water pump as the 1275 overhangs slightly?
Yeah i have also read this might be the case, we'll have to wait and see!