what happenes when you scratch aluminium? (like the surfaces that join the S/C to the T/B)

There really is not a whole lot you can do. Make sure if you made a BURR that you trim that BURR off and the fillthe hole with a dab of silicon sealer....

thanks for the info,

I was wondering what happens to the aluminium. what properties does it loose. what are the actual adverse results that require filling of the burr with silicone.
Titanium when scratched will actually deteriorate and the point of such slow decay will be the burr or even a dent. in case of titanium ( like the pistons, rods...) it requires to be buffed. Is aluminium the same?

A sealing surface will not go through the type of cyclic loading that a con rod or piston will go through, so it shouldn't be as big a problem.

Con rods with a scratch could fail because that scratch causes a 'stress riser', which is a point at which a crack could start more easily than if it was a smooth surface.

Because the intake manifold or SC surface isn't loaded like a con rod, it shouldn't be a problem.

Big thanks, reassurance is a great thing