What would a machine shop charge for a valve job and a head resurface?

This car is my daily beater, so I dont want to go over the top with it. It runs great apart from it using water.

Do I zip tie the chain to the cam sprocket and remove the sprocket from the camshaft?

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Ben

'85 500 SEL
'85 928S2
'88 560 SEC
'90 750i