First up either make a gasket to fit on the head from scratch or use a standard gasket (in this case a type IV inlet manifold gasket - it was slightly oversize in comparison the ports which was taken into consideration when match porting.

Next up place the gasket on the manifold ensuring you line up the bolt holes to check if you need to port or not!

I marked around the ports with black marker (engineers dye could be used but didn't have any - this sufficed).

Holding the gasket firmly in place, scribe around the inside - a proper scribe will help here...not a corner of a screwdriver or similar.

Here we are ready to go...

Using a tungsten carbide cutting bit in a die grinder enables you to take off material quite quickly (so go slowly!). I found some WD40/RP7 helped to stop the aluminium clogging up the cutting bit. I found a bit with rounded end helped to avoid cutting in any steps/edges into the manifolds.

I then used a sanding flap wheel to tidy up the harsh scratches left from the cutting bit - this one was 120 grit.

Ports were now done, I decided to ensure the manifold base was not warped. First off mark the base with dye or marker pen.

Find a perfectly flat piece of glass. Then using sandpaper (I started with 240, then used some 400 to smooth out any scratches) steadily rub the manifold across the surface until the dye/marker is gone (but don't go too nuts and take too much material off).

Even though these manifolds were new, I thought I'd check. Used manifolds subject to heat and overzealous manifold nut tightening would benefit greatly from this process.

There ya go....nice and flat. Ready to bolt on! (after a thorough clean)