All Small Six Which cylinder head?

[Otto]

Took the van for an extended test drive to check my work. The speedometer is now pretty durn close to the app on my phone, so I’m calling that fixed.

The engine ran well with the 160 jet size; I didn’t see any alarming lean readings from the AFR gauge and driveability was excellent. I’m thinking this setting will work for my engine. The van will get driven more when summer rolls around and more time behind the wheel will further tell the story.

Thanks to all that contributed to this project, it’s appreciated. Sometimes it takes a village…

 

[Otto]

Just to follow up with a summer driving update:
I drove the van to a local Econline-centric event at the end of June, and noticed the AFR meter was reading lower than it was when I was testing things out in January. Plus I could tell it was running richer due to the exhaust smell. Having windows that open on the rear doors tends to offer clues on what’s happening in the engine.

I got some new jets in the 1.55mm size as I had drilled the carb’s jets larger. The new jets are one size smaller than the drilled jets that were in the engine. With these new jets, I was seeing 14s and 15s on the meter cruising down the road- this is higher than before where it was only in the 13s with an occasional 14.
On the latest test drive w/new jets installed, the spark plugs look like this:



I pulled #1, 2, and 4 and they all looked very similar. This is after driving at 40-45 mph and turning the key off and pushing the clutch in, coasting off the road. I was able to pull the plugs from the driver’s seat even with a seat belt on!

Any thoughts on the plugs? It seems to run well. The engine is only happy with the idle at around 12.5.

 

[DON]

Plug looks good in the photo
With the idle around 12.5, let it idle for 15-20 minutes and check the plugs again. I would say it it is happy there, leave it and see if any negative issues arise .
Assuming all other aspects are correct- timing mostly