I think the grills had a different bolt pattern. The 63 grill was only made for one year. Whereas the 64-66 mounted the same. You could use it, but you would have to drill it out to mount the later grill on tghe earlier support panel.


http://s971.photobucket.com/albums/ae197/jon63c10
1963 c-10 shortbed stepside 427 BBC T16 HD 3 speed
1963 c-10 shortbed fleetside 348 "w" 1st gen big block & powerglide