250 6 cyl., 283, 327. 350, 396, 400, 427, 454, 502, and a 572, take your pick.
Any GM engine you want to put in it will work, 283 up to a 396 big block was offered in V8's in 1966, also the 250 V6 was offered.
Yes. They should bolt right in.
No.
yes
Yes
Yes
No, they will not interchange.
yup...
A standard Chevelle frame will not fit an El Camino as it was based on the station wagon frame
Doors from a 1978-87 El Camino or GMC Caballero
no because it poops butterflys and rainbows !:D
I think '65 and '66
No, they're 2 totally different bodystyles