OK, it's not "in" a Cobra, but it is a genuine 1966 289 Hi-Po engine. The same engine that WAS in the original small block Cobras:
Mobil 1 15w-50. No additives needed. Over the past 10 years I've put 44,000+ miles on it. Many of them at high speed for extended periods. No measurable wear, no leaks & great
oil pressure.
Z.