I use Ospho on parts which I don't plan on epoxy priming. Epoxy primer does not get along with Ospho unless the part is meticulously cleaned of all of the byproduct of the chemical conversion done by the Ospho. I don't risk it for body panels which I have to pay a painter thousands and thousands of dollars to apply.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission