64-65-66-67 chevelle.
No, they will not interchange.
Any 1978-87 El Camino or GMC Caballero
1968-72
65 66 and 67 will interchange.
yes it will, they are the same frames.
A standard Chevelle frame will not fit an El Camino as it was based on the station wagon frame
No
No.
Yes, 1968-1972 had the same frames.
No
From what I understand:1980 & 1981 complete grill with the headlamp bezels will interchange
Yes