View Full Version : About to do an engine swap! What shall I look for?

07-01-2006, 11:49 PM
As the title says, Im about to swap the engine in my 89 SC. My old engine has at least 200K (true miles unknown) and has a head gasket on the way out. I came accross a guy who had a 91 SC with 36K miles on it. During hurrican Gaston a couple years ago a rather large oak tree came down on the garage his SC was in an smashed the roof and rear of the car. Anyway, he pulled the drivetrain and was going to put it in a 97 Mustang until he was informed that his Mustang would no lnger pass our states required emissions inspection. The engine is super clean and doesn't look like its really even broken in yet. I bought the assembly as a complete drop out with the front suspension, crossmember, and all brackets and accessories. My question is basically do I need to look for anything on my car or this engine during the swap? Are there any wiring harnesses I would see until its too late? Will it have to do any modification to put a 91 engine in my 89 or should it just wire right up? My care is a 5 spd and this was an auto, witll this affect the swap? I have in the past upgraded later model mn-12 tbirds (94-97) from v-6 to v-8 cars rather easily, but with those the wiring harness unplugs in the corner. I can not find any such plug on my SC. Any insight will be greatly appreciated.

07-02-2006, 04:13 PM
Just use all the wiring and EEC from your 89. The engines should be mostly the same, maybe egr/no egr, things like that. Just put it in like it was your 89. There are some differences in color coding between the two harnesses but wiring should be the same functions. The cam in the 89 5speed is a bit more aggressive than the cam in the auto. John

07-02-2006, 11:19 PM
It shouldnt be too bad. I once put a 90LX engine in a 93LX and the wiring plugs for the injector harness, and distributor harness were completely different at the firewall, so I swapped the harness and made it work. Not sure what year they changed plugs. Just see if the plugs are the same before you get it installed, im sure that would have been easier....

07-03-2006, 12:15 AM
The cam in the 89 5speed is a bit more aggressive than the cam in the auto. John
"a bit more agressive"? Technically it's a little bit, but a "little bit" makes a big difference at the track.

Original Owner, 89 XR-7 5 spd