Absolutely. You will need to either change it over to a carburetor or install the computer and wiring harness for the fuel injection, and change the fuel pump as well. But otherwise, it will bolt right in.
Pretty much any 350 Chevy engine from 1968 to 1987 will work.
First of all Chevy did not make a vortec engine in 1987 or 1995, those engines are TBI / Throttle body injection engines. And yes they will interchange with no problems.
The 1987 Chevrolet El Camino takes 18" replacement windshield wipers on both sides front.
v-12
Yes, it will.
check the frame rail under drivers floor.
ASSUMING ITS A 305 ITS ABOUT 475 LBS WITH ACCESORIES
use your pre 87 unless you have rollers or the application calls for +5 or other.vortecs have rollers.
No if you want to use the same transmission. They have different bolt patterns.
I have an 86 with a 4.3 and it regularly gets 21 - 23 miles per gallon combined (city/hwy). I can't answer for the 5.0
Yes
The idle speed on a 1987 Chevy Celebrity is controlled by the engine computer, there is no way provided to adjust it.