vacuum advance ?

I was under the impression that all vacuum advance modules points, electronic, 6 or 8 would physically interchange. I have swpped them around to get different advance amounts. The number of degrees they add is stamped on the arm (double it for crank degrees).

However, if the one you are trying to swap in won't mount into the same hole on the advance plate will give either more advance if its closer to the pivot or less if further away. I wouldn't mess with it and would just go to the local parts store and buy a new one for your car.