I seem to recall the same cat symbol valve covers being in the Gas Rhonda long nose Mustang AMT had way back when. I had or even may still have a chrome tree that has them on it with some long long headers. Just looked at the Dyno Don kit I have and the tree is different. AMT missed the mark on those valve covers, and the heads. The real ones are W I D E ! Johan got it closest I think but even they are a bit off I think. These are the Johan ones. Ignore the rest of the engine, it's a hodge podge of parts to accurize the cammer.
Dave, do you want to be common or uncommon? Commen, bbc, hemi blown Yada yada........boring...... lol. (Kind of hints a Top alky dragster...) Uncommon, turbos! Semi uncommon, sonny headed tunnel rammed. This may have changed since I've gotten out of racing....... Names have been changed to protect the guilty....(well ok, me! Lol)