Ford 5000 oil blowback

[CPB123]

Hi all, I've got a '70 ford 5000 diesel that just started blowing oil from the filter canister on initial start up. Happened yesterday and today, changed oil and filter, made sure all seals are good. Does not appear to be leaking during operation, just first startup of the day. Any ideas?

Thanks

 

[5030]

Crankcase vent tube is plugged. The block is pressurizing.

 

[catskill_tractor_guy]

This is 18 years old, but I'll reply since others read this. I had that happen once after I did plugs and wires. I had the distributor cap miswired and it was exhausting through an intake and spraying oil.