Quick Fuel SS-780 tuning suggestions

[Loadco]

How are you attaching the O2 sensor form the LM2. If you are just using the Innovate tail pipe clamp your readings are probably not accurate. I had that problem with my LM1. You need to attach a length of tubing to the inlet on the tail pipe clamp to get it up inside the side pipes to get a good reading.

[SwiftDB4]

I would agree with both of the last 2 posts. If your Oxygen sensor is too close to the end of the pipe it will read leaner than true. Also check your ignition, distributor cap, etc. My MSD cap had a damaged center contact that caused carboned plugs. I wouldn't go leaner on the main jets though. The QF 750 on my 427SR runs 72/78 mains.