I took a good bitch to a good dog I had heard about from a mate of mine once ,what looked very similar to your pup,heavy boned and a right lump of a dog same type of coat and head ,when I questioned the look of it I was told don’t let its looks fool you,it was an Airedale x greyhound x pit bull ,all the pups turned out to be demons at work,good luck with the pup,wf