This is prolly a dumbass ? but will a d17 crank fit a b17 in anyway if slightly modified?

No. The bore spacing on the B17 is very different from the D17, so the rods won't line up with the pistons when you put it on the block. And before you ask, no the D17 crank cannot be modified so the rods line up.

However, if you're interested in selling that D17 crank, and it's pristine, I'm very interested.