I just recently sold my '72 F250 and got an '81 F100 stepside. It's got a 300 I6 in it and when we went to look at it, it cranked up just fine but my dad noticed it was spittin oil outa the dipstick real bad so he lifted the dipstick up and it spewed oil everywhere. It had blow by. We bought it thinkin "it starts up too easy to have bad compression, maybe it's just a vacuum problem." After tinkerin with it we found a vacuum hose just Layin around and we plugged it off, now it doesn't have blow by, but it's still leaking oil out of the dipstick (atleast we think) we went to the junkyard today and pulled a dipstick outa a truck that was wrecked and put it on hopin it'd fix the problem. It's still blowin it up through the top. My dad looked at the Vacuum lines and realized the line comin from the PCV Valve is going to the carburetor. The guy we bought it from owns a shop and works on new car. He told us he doesn't know much about these of trucks and we think they just hooked the vacuum up wrong. We haven't ran a compression test yet cause we don't have a compression gauge. Any advice would be more than helpful guys. I've looked at all kinda of diagrams but I just can't make sense of them. Thank you so much in advance.

Jace

 

The PCV valve should be hooked the the big vaccume port on the back of the carb make sure the PCV valve isn't sticking either

 

There should also be an air inlet on the other side of the valve cover, it lets air in to replace the volume of blowby gases sucked into the intake stream.