Experiences with larger breed puppies?

So admittedly this is my first dog – we didn't set out to get such a large dog but instead ended up finding a stray and when we couldn't find his owner/people in the area claimed he was dumped we gave up and decided to keep him. When we found him he was about 30lbs – we've made it to the 7month mark of having him and he is now 60lbs. He looked full grown when we got him but he had a huge growth spurt. He's presumably only a year old maybe slightly over a year (barely)because looking back he was definitely still a puppy maybe like 5-6months old. Anyways- we are unsure of his breed we're thinking lab pit? He is BIG and VERY PUPPY and still has so many puppy behaviors even at his large size and age. Did anyone else with a big dog like this experience a longer puppy period? I just see a lot of people claim their dog calmed down at about a year and he has definitely improved but is still very puppy. It just feels like there's no end in sight to the crazies. I'd love some insight from anyone who raised a larger breed of dog and how they behaved/when they finally started to get some sense/calm down.