Difference between 470 valve spring and Ford?

[nola mike]

After finding a busted intake valve spring when winterizing my boat, I started looking for a replacement. I used Ford 460 parts for a head repair last year, but it appears the springs are different between the auto and marine apps in that a shield is on the marine version, but does not appear on the auto? Does anyone know the difference? Not a huge deal, as it's a $10 v. $2 part, but I'm curious...