Bringing this back up. Finally installed my A/F gauge and as expected, the engine is on the rich side.

I am impressed with myself for getting it in the ballpark just tuning by ear and feel. The truck runs pretty well and has no hesitation. It is not "pig rich" by any means but based on the reply above, I have some work to do.

The main thing I was looking for with the gauge was cruise A/F ratio. Currently, it's under 14. 70 mph seems to be the sweet spot for best A/F ratio at around 14.2 but the RPM required to keep it at 70 likely negates any benefit of a leaner mix.

Most of the time the gauge was between 14-13 with dips into the 11-10 range when accelerating and 16-17 when you mat the gas from a roll. After the initial opening, it recovers and goes back to 13-14 depending on how long the throttle is needed to get up to speed. Closing the throttle creates a momentary rich condition into the 12-11s but then it recovers.

Idle mix was on the rich side just under 14. I may have a linkage/cable issue because there are times when the throttle blades don't seem to close all the way without pulling the throttle back with my toe. My throttle return bracket is from a small block so it might not be entirely correct. Will have to look into that one. That's been there since I got the truck so yes, I need to get on that. It also takes a while to idle down after a stop but it's a stick with a heavy flywheel.

Besides that, I have not played with anything on the carb yet, not even the idle mixture screws. Reading up on tuning techniques, I think I may be getting in deep with air bleeds which unfortunately are not real adjustable on a garden-variety 3310. My quaint hope is that one of my Thermoquads will be more tunable in this regard, meaning no drilling of fixed orifices, changing metering blocks etc. and will potentially do a better job with cruise A/F.

I also need to drive with a vacuum gauge to see if the power valve is coming on at the right time. Not sure yet but based on the gauge, I don't see a big rich spike when accelerating so it must be fairly close. It's a 6.5 now.

So the main goal right now is to get the A/F ratio as good as it can be with this combo of parts. I believe the Holley might be limited in it's tunability but again, I have not gotten too deep into this yet so we will see. When I get to the high point I'll start thinking about swapping the cam and intake.