For the rear end I would try a junk yard and get a truck 9" or 8" rear end. They are common and usually cheap (I get 9" truck rears for about $100). That would require a lot of fabrication (cutting the tubes to length, salvaging the spring mounts from your old axle, welding experience required). But if you are like me I would rather save a lot of cash and have fun with my welder while I'm at it.
The 351W is a awesome motor and it would surely blow up the stock 6cyl rear in your car. I made the mistake of building a 351W based 550HP 408ci stroker and putting it through a stock trans and rear.