Yes, you will need a new K-member.
the rearend would work, but it would have 1-wheel peel which would keep it from blowing.
transmission would need replacement
Fuel system wouldnt work with a carburator
Also, the gauges are electronic, as is much of the AC system. all of this would need to be replaced, and the AC would have to go.
Dont forget the suspension would have to be changed to handle the weight of a 351.
if you do all this, you will NOT be able to legally drive this car. The OBD computer will no longer be in service, and the car will not be scanable for inspections, leading to failure.
essentially, for the cost you could drop a procharger & supporting mods onto the V6 and end up with a faster car. and one that is legal.