In my 489 Ford, I started with 3924, common one for the street for us, I found it was too cool and wouldn't foul, but never cleaned up

So I went 3926 and closed the gaps to .032 (I am not running an MSD) and it was dramatic, with no downside

So long story short, I think the 3923 would be far too cold for street driving, I would try a 3925, standard Cheapo autolight

This does assume they are getting wet with fuel and not oil fouled