[davepl]

I thought 307s were very low compression... doubt it should ping on 87 octane. You really want vacuum advance, it's not just an emissions thing. Without it you're going to have very retarted timing at idle which will heat up valves, heat up the engine, and suck for driveability. You might be able to get it to work with a lot of base timing and less mechanical advance, but then you'll be fighting part-throttle issues.