Any recommendations on a good quality Air/fuel ratio gauge?

[Back N Black]

This on at summit, what do you think?  https://www.summitracing.com/parts/atm-3370

[Kern Dog]

I installed an AEM gauge several years ago and it is still working well.

[b5blue]

Thanks I was heading in that direction but recent reviews claim defective batch of sensors. 

[Kern Dog]

I cannot vouch for what they are making nowadays. I bought mine maybe 8-9 years ago.

[Back N Black]

I installed an AEM gauge several years ago and it is still working well.

Was it money well spent? Were you able to tune the car and feel a noticeable difference? Better idle, cleaner plugs?

[Kern Dog]

What it did for me was confirm a few things. I bought it because I thought I may be running too lean, leading to detonation. I was wrong...I was running too rich. It was helpful for giving an immediate response for changes in idle mixture screw settings, jet and power valve changes, timing adjustments, etc. I've learned that the "ideal" 14.7 to 1 ratio is only applicable to 100% true gasoline. The up to 10% ethanol readings need to be about a point lower. WOT needs to be richer, something in the high 12s, low 13s. The gauge really shows how wild the numbers swing during normal engine operation. Looking at the numbers swing around while the engine seems to run normally really surprised me.
I only have it plumbed to one header through a single O2 sensor.