How strong does Goku become at the end of Dragon Ball?

[SIAD]

After his fight against Piccolo, Goku experiences a Zenkai boost.

How much does his power increase? Could he defeat Piccolo with medium-high difficulty instead of high difficulty?

 

[DBZAOTA482]

After his fight against Piccolo, Goku experiences a Zenkai boost.

He didn't. He wasn't close to dying (Kami healed him before he passed out).

Anyways, he was weaker than he was at Beginning of DBZ. Not a whole lot tho due to Goku slowing down to becoming a family man.