I have a Poulan 365 60cc tore down to put crank bearings and crank seals in. It might be a little over your head installing bearings and cranks though. 
Maybe just staying with a top end rebuild and carb stuff to learn on first.
		
		
	
	
		 
	
Someday to go back to this with 20"
		 
	
Here is a Poulan 415 I didnt have to go as deep with. You could start with something like this. Runs a 24" with ease in hardwoods.
		 
	
		 
	
415 video after rebuild Poulan Pro 415 after carb soaking - YouTube
	
		
			
		
		
	
				
			Maybe just staying with a top end rebuild and carb stuff to learn on first.
 
	Someday to go back to this with 20"
 
	Here is a Poulan 415 I didnt have to go as deep with. You could start with something like this. Runs a 24" with ease in hardwoods.
 
	 
	415 video after rebuild Poulan Pro 415 after carb soaking - YouTube
 
 
		