63 lesabre 401 nailhead to rebuild or not

[vinny02126]

here's the situation, I bought a 63 lesabre, it looks great and actually runs strong but I am getting a ton of blow by out of the oil filler cap. when at idle you can't really see an issue from outside the car but as soon a sit goes under power to get off a light or something like that it leaves a cloud of white smoke from the exhaust. I am sort of just getting into doing my own mechanical work so I am not good at diagnosing, and a total rebuild is beyond my skill set. I want any recommendations people may have as to what the cause is and what the solutions may be.
There are no leaks I can see, and there is not any noticeable mixing of oil and coolant, honestly I think Id prefer a blown head gasket than a rebuild Im just afraid it may need the rebuild, whats the best way to figure it out

 

[HotZ28]

You would need to do a cylinder leak down test to determine what the problem is. If the car sat for years, the rings may have lost tension, and that is where the blow by is coming from. A good compression test & leak down on all cylinders should tell the story.

 

[1380Ken]

How much oil does the engine use? If it runs good I would just keep adding oil.