Driveability of high compression cars

[Keith Tedford]

Since 1997 we've put about 28K miles on our L78 Chevelle. It works fine on 91-93 octane gas. You have to get the advance curve set up right with no more than 34 degrees total. We have a 10.25-1 455 in our '72 Lemans Sport and it works fine too on the same gas. Running slightly rich helps as does a colder thermostat. Block off the heat cross over in the intake as well. It's the little stuff that makes things work. Stock engines can be as much as a point blow what is advertised. If you have a blueprinted engine that is a true 11-1, things could be a little more difficult.