Posted by Lowell Brown
Sorry to be so late to contribute to this thread.
Ferrari aluminium sand castings are very porous. The Factory usually painted both the inside and the outside to seal the castings and prevent them from weaping flluids.
When I repainted the outside black wrinkle paint on my 330 cam covers, I asked a Ferrari expert, David Smith, what to put on the inside.
He told me to first spray on a light coat of Green Zinc Chromate Primer --- the stuff you see on airpalne frames --- and then paint on Red Glyptal Enamel --- the stuff used long ago to insulate the wires after an electic motor was rewound.
After I made a flywheel inspection cover, my local mecahnic, Carlo Durante, recommended that I paint it with VHT hi-temp Engine Enamel, SP-127 Universal Aluminium. This matches the paint on the block very well.