Its a B as it is the 2nd series shape ( same as my panel) I am going to work out how to link to some pictures.
It has stickers on it from the 22nd Winternationals pit access - so I am guessing it was used to tow a race car & that is why they went for the big block.
I am thinking about maybe sourcing a diesel for it in the future - may be a bit cheaper to run ! Gas is about the equal of $8 us dollars a gallon here !