Hello, I m sorry no one could help you earlier. I will be glad to help if you still need it.
The 3200 series of engines originally had only two piston rings. These were Keystone type rings and were terrible at sealing when the engine idles too much.
The 3208 truck engine had lots of trouble from idling.
If you place the engine under load for a few hours, the blowby should decrease. After eight hours of HARD work, it should seat the rings and have less blowby.
If the engine if left idling for any extended period, the blowby can return.
I would not be concerned about to much blow by unless you are seeing a lot of oil with it.
Many of the older engines worked better after a good "Break-In" period and must would need eight hours of hard work to do it. A few would need longer times but, it mainly needs to be at normal operating temperature and under load to reach that "break-in" requirement.
Please include the full machine serial number with your reply if you need further help.