1970 Buick Skylark 350 4 bbl intake manifold, posi rear axle/end bolt on, headers, quadra-jet....

I am searching for a 4 bbl intake manifold for my 70 Lark. Does not need to be original. I just want to convert from 2 bbl to 4 bbl. I am also looking for a posi rear end/bolt on rear axle and possibly a set of headers and Quadrajet carb. Thanks in advance for any assistance.....