Novice needs help

[Hook'em]

I have a couple of questions that I am sure someone hear can help me with. A little background on my truck: I inherited it from my Dad a couple weeks ago. I have very little information on the truck, which is my problem. He had the truck for about 10 years and it was mostly redone before he bought it. I know the truck is a mut because the VIN numbers point to '69 but the grill and hood point to '71. My questions for today have to do with the engine. I found out that the engine has a canister type oil filter. I understand that somewhere on the block are numbers that will identify the year of the engine, so I can get the right oil filter. I also understand that the canister can be converted to a regular oil filter rather easily, I would like some opinions regarding this conversion (I assume it has been done around here before). Finally, there is a hole at the back of the engine that would appear to need some type of filter/breather, but I am not sure. Below is a picture of the canister oil filter and a picture of the hole.

Sorry for all of the ignorance, I wish I was able to talk to my Dad about the truck before he passed. I have about as much knowledge as someone who found a truck on the side of the road.

Thanks in advance for any help.