The answer is NO
From 1964 to 1969 chevelle and elcamino front ends are the same,which means their parts are interchangeable.
In 1970 the front ends and doors were no longer universal,so from Oct.1970 to Nov.1978 elcamino front ends and doors had to be replaced with other elky front ends and doors(station wagon fenders,doors,and front clips will work also)however the 1970-1972 chevelle cowlinduction hoods will fit 1970-1972 elcaminos.Engine wise all Chevelle and Elcaminos small and big blocks are interchangeable,just remember when using headers fabrication is some time needed,and some times headers will not seal or fit properly on the front left(drivers)side at all.
NEW IN 2003 you can now get brand new fenders and door skins for 70-72 elcaminos,this is a very big deal because up til now you had to buy used doors and fenders because no one made them but thanks to the guys at original parts group,you can now order brand new skins and fenders
Visit original parts group through my favorite links page or call for your FREE catalog at 1-800-chevelle
Thanks again OPG.
ELCAMINO FACT
between 1959 to 1987 chevrolet produced 976,000 elcaminos.