Has anyone tapping an oxygen sensor in the exhaust, connected to air-fuel mixture gauge in the cockpit? It would seem that this would be the accurate way to select the proper carb main jets and power valves.
yes! my oxygen sensor had always been my nose . the back up was my eyes . if my eyes water its to rich.
I did a little experimenting with one hooked to a voltmeter in the cab when I was sorting out the blower on my flathead. I had lakes style headers and just made a new cap with a bung in it. It worked fair, but was too quick changing.
That's still pretty interesting though. I wonder if it would read more constant if the sensor was not at the far end of a closed chamber like a capped lake?
Well, the cap was right next to the tied-in exhaust pipe. It worked well enough to make some changes, you just had to average out the highs and lows.
I put a wideband sensor on my 55 (blown big block), it's interesting....Holley double pumpers run kinda rich at normal driving speeds. I also put one on my old truck (stockish 454 with a Qjet), and it looks pretty good.
I used a wideband one from Innovate Motor Sports (innovatemotorsports.com) to set the mixture on my Rochester FI unit. Works great. Made a removable adaptor to fit into the tailpipe as I had already had the exhaust coated by taking a piece of 1-7/8" tail pipe about 2' long and slipping it into my 2" pipe with the bung welded into the smaller pipe.