I got two 02 sensor bungs welded into my exhaust system last week. One for each side. We're talking about a '66 big car - in this case my 98 convertible, but also eventually a '66 Starfire. Both have 455's, 800 cfm qjets, HEI's, Edelbrock performer intakes, and factory dual exhausts. Slightly warmed over, not lumpy.

I'm considering the Autometer 3870 kit or 8170 kit. Or Innovate Motor Sports dlg1 (p/n 3891). Any experience or opinions on these choices?

An A/F gauge would be a worthy upgrade to the vacuum gauge I've used for 10 years or so in the glove box.

The 02 sensor/gauge package needs a switched source providing about 5 amps. What circuit would you tap into? I don't want to tap the HEI, it needs all the voltage it can get. I'm thinking maybe wiper motor, or the starter motor.

What are your views on which switched circuit to tap?

 

Just plug into the IGN or ACC terminal on the fuse box. Use a 5A inline fuse. Done.

 

The innovate uses a large sensor controller box that can be a pain to hide - about the size of a laptop power supply.
The auto meter looks similar to the AEM - the controller is built into the gauge.
For just carb tuning and maintenance, and of them will work well. I would recommend using a gauge that has both digital and analog readout. When glancing at it it's best to have the analog sweep so you know where-about it is. But when actually cruising or tuning, the digital readout is good to know where it precisely is.

 

Just to close this out, I did tap the ACC circuit at the fuse box per Joe’s advice. Works great.

I mounted the sensor controller box on the cabin side of the firewall 6” or so above the gas pedal to keep it away from heat and electronic noise sources like the modern radio and HEI.