Ok so here is my first real Noob-Mistake...
After the engine was bead blasted the machine shop spent a lot of time cleaning out the galleries etc but just to be sure I did a second clean to ensure I got all the glass beads out. After this I ran the cases through the dishwasher as a final prep.
Unfortunately I didn't consider the fact that the missus uses vinegar instead of rinse-aid and the eco-friendly dishwasher soap is really caustic..... I should have just run it with a mild detergent but it was late and I was a bit tired.
Anyways the result is my nice silver engine is now a kind of gun-metal grey?
I was intending to paint the cases so it's really not a big deal but in the interest of saving somebody from making the same mistake I thought I'd post my error.
To be honest the more I look at it the more it grows on me... the photo doesn't really show it so well but when I put my polished side covers against it it looks pretty cool.... kind of an alternative patina.
I might just roll with it as is...