Here is a Heathkit. Seems pricy though.

https://www.ebay.com/itm/VINTAGE-HEATHKIT-MODEL-CI-1080-EXHAUST-GAS-ANALYZER-1974-/132921577917?_trksid=p2349526.m4383.l4275.c4#viTabs_0

If you don't find one, drop me a PM and I will dig mine out. I am well retired and no longer work on air-cooled VWs.

That does look like what I remember seeing in the past. My dads' buddy used to use it for exactly the same purpose; tuning dual carbs on TYPE I's & TYPE II's. I always appreciated the Unysin but I knew there was more to be learned from CO monitoring.

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__________________
I do not 'believe'. I have no use or time for this distraction. A'priori is antiquated furniture that clutters the mind and deteriorates society. Instead I investigate, research, scrutinize then choose from data what best serves as a suitable answer until a new idea or material is presented. Then I start the process again.

If you don't find one, drop me a PM and I will dig mine out. I am well retired and no longer work on air-cooled VWs.[/QUOTE]

PM sent

__________________
I do not 'believe'. I have no use or time for this distraction. A'priori is antiquated furniture that clutters the mind and deteriorates society. Instead I investigate, research, scrutinize then choose from data what best serves as a suitable answer until a new idea or material is presented. Then I start the process again.