The outer covers on mine looked like they'd been left rough cast, then attacked with a wire wheel in a drill. In other words, they looked pretty sorry!
I started with 120 grit wet & dry to get everything level again, then went to 360 grit to get the big scratches out. I then went to 600, then 1200 grit.
Final polish with solvol autosol and they look just great.
Cost me about a fiver so far, plus a couple of hours saved where I could have been sitting in front of the telly with the wife watching tawdry 'reality' shows!
I'd post a picture but our camera broke last week :cry:
Ironically, the rough cast items (gearbox shell, crankcases, cylinder head) were reasonably good, but I put that down to the fact they were originally painted, and the PO mercifully hadn't 'got round' to them.
Z plates next... :roll: