Is there a particular crown vic front sub I should be looking for to swap into my 57 f100

 

There are quite a few threads here and in the 53-56 section on using the later Crown Vic suspension on the stock frame. Personally, I think they are too wide but if you don't mind running the modern wheels with lots of ofsett they seem to work fine. I have a friend who uses the earlier Crown vic front stub and it makes a nice set up but is more work.

 

03+ for the late model, bolt in IFS. I think 03 and 04 had aluminum control arms.