What is your compression ratio? Granted, most cobras are built with engines that would require 91/93 octane but if yours is say 9.5-1 or lower, then that won’t necessarily be so.
BTW, on the
oil leaks; I recently (last 4 months) have been running mine with an electric vacuum pump. I know most who run them are actually looking for more power and I'm not. However, I thought that if I could bring the crankcase pressure down to even just a little under atmospheric then many of the little leaks that MIGHT happen would be nipped in the bud so to speak. I’m glad to say that this has worked out quite well for me so far. When I get a little more time I’ll do a write-up with pics of what I did.