i bought my 86 gxl a year and a half ago form a kid. Well in the purchase he told me he had another motor for it he was going to throw in for me. He said that it was pulled from a wreck with about 75-80k miles on it but he could not tell me the year of the vehicle it came out of. I plan on taking it apart once summer comes and was just wondering if there is a way that i could tell if it is a s4 or a s5 engine. Also if it matters when i buy a rebuild kit does it matter if it is a s4 or a s5 motor. i aslo want to try to do a street port on it should i atempt it or leave the porting to someone who does it regularly and knows what they are doing. thanks for the help.

easy, s4s have and egr that bolts to the center iron the s5 does not if its a 6 port na motor, if its a turbo the s4 had a twin scroll set up and the s5 had a single waist gate actuator. there are alot of little diferances as well but look for the egr on a na motor i believe the s4 turbo motor had one too but the s5 did not.

that helps i due know it is a n/a becuase it had the manifold still on it but i will look for the egr bolts on the block to see if it is a s4 or a s5. Thanks for the help and any idea's on if the motor will be good for sitting maybe 2 or more years.

wouldnt have a clue and with no history on the motor your basicaly rollin the dice on it. look in the exhaust ports for rust and corrotion. flush out the cooling jackets and dump atf in it and turn it over by hand now and then untill your ready to try and run it or pull it appart.