Tetraethyl Lead IS the major component in leaded race gas that makes it RACE GAS!!!
Yes there is unleaded race gas on the market, but I've never seen it with an octane rating much over 100. Foe example, Sunoco 260 GT Plus is rated at 104 using (R+M)/2.
Leaded racing gas is typically available between 110-116 (R+M)/2.
How much octane does a given engine need? This would be the better question!
For example, if you own a 60's era muscle car with say a 12-1 compression ratio, you better run at least 100 or better.
But what if your running say a modern aluminum race head, long rod V8 with a 13.5-1 compression ratio with full ignition timing?
Anyone have an answer? (This is what I want to run in my weekend warrior).
Mark