Thanks for the excellent threads on 308 carb jetting and synchronization. My 308 has been in storage for 12 years, now back to life. Needless to say, it wouldn't idle at all. Strangely, the idle jets were 45's. I'm up to 57's (1.60 times increase in jet area) and I have 60's to try (1.78 times increase in jet area). I'm now achieving excellent idle but still sporatic popping back at 2500 RPM. I've gone up 15% in mains and air correction to compensate for today's fuels (140,210), but I'm wondering if this is enough considering the required change in idle jets. Are the main jets contributing to popping back? Thanks to all.