Comprehensive Test Regular vs Premium

Premium, higher octane is good for higher compression engines/ racing as an anti-knock agent. Beyond "premium" is race gas. Unfortunately, our beloved 'A' bodies with 10/1 compression fall into this category. I recently did a resto rebuild of a 1968 383 and we brought down the compression a 1/2 point because of the gas. Also in the rebuild am running a roller cam due to 'modern' oils. The world is changing and I am still learning.