if it came stock with the 305 it should bolt right up, but im no expert Z-44) yes i have a 1985 el camino that originally had a 305 and swapped it for a 350 pretty easily. you can actually fit a 383 with minor changes (different motor mounts etc.)
305 V8
150 ponys
305 cu. In. V8.
Try nada.com
58
The 1985 Chevrolet El Camino dipstick length is 27 inches. The dipstick needs to be exact in order to measure the oil properly.
More then likely it is a 305
Your best bet is to go to jags that run they sell mounts, headers, and a manual for this swap
ASSUMING ITS A 305 ITS ABOUT 475 LBS WITH ACCESORIES
Most El Camino Have 8 cyclinders either a 305 cubic inch engine or a 350 CI engine. some of the early 60 models had 6 cyclinders.
none,they came with 305's