87 RS V6 to 91 L98 swap
 

2.8L V6 700R4, 3.42 open drum brake rear. Lots of miles. RS package - upgraded buckets, leather steering wheel, 15" Z28 wheels body matched paint, factory gfx, no stripes.
This is what it looked like when I bought it.
http://www.blk-wdw.com/87rs/87rs002.jpg
Ran lousy. Spent a little time messing with setting on some stuff, and re routing plug wires ( there was one wire laying on the EGR piping so it was arcing and cracked )
Ran and drove better but still not right, motor sounded unhappy. I think the Mass Air Sensor was on the fritz.

Swapped my IROC wheels on and quick sprayed over the pink bondo.
http://www.blk-wdw.com/87rs/87rs008.jpg

Next up I am getting ready to pull the V6 to swap in a 91 5.7L and auto.

Re: 87 RS V6 to 91 L98 swap
 

OK, I am going to document the swap as best I can.. though I tend to get rolling and forget to stop and take pics. This will end up as a decent guideline for anyone attempting a V6 - V8 swap, or even just engine removal etc.
Here's the car as it sat this afternoon.. in the barn waiting to go.
http://www.blk-wdw.com/87rs/87rs023.jpg

Shot of the mighty 2.8L soon to be removed from the engine bay.
http://www.blk-wdw.com/87rs/87rs024.jpg

Here's a shot of where the VERY important C100 connector is. There's a few relays somewhat hiding it. In any sort of swap this is where a good deal of wiring comes through. It's split into 2 separate harnesses. One side is the lighting harness. This will stay with the car. The other is the engine harness.. this gets removed. Depending on your exact swap, this can sometimes be reused. In my case I am using the harness from the new engine. This will involve careful cross reference of the C100 pinouts for both year vehicles, 87 and 91. Because I plan to use the stock 87 INSIDE harness, I will be repinning the engine bay connector on the engine harness to match up with the 87 stuff. GM in their infinite wisdom changed pin locations through out the 3rd gen run. I have no idea why. One thing to pay attention to is the wiper setup. There is more than one style through the years and you may have to either cut the harness end pigtails off and splice into your new harness to use your existing wiper motor, or you can swap to the matching style motor that came from the donor vehicle, the same as your engine.
http://www.blk-wdw.com/87rs/87rs025.jpg

Re: 87 RS V6 to 91 L98 swap
 

Now the first step.. remove the battery. Seems like a no brainer.. but just make sure you do it. If it's stock it's an 8 MM head on the battery terminal.
http://www.blk-wdw.com/87rs/87rs028.jpg

Next grab your tools - socket set.. 3/8" drive and 6" extension 10 and 13 MM socket. 1/4" drive 7 MM socket. A flat head screw driver and a phillips head.
That's all you really need to get started. You can tear down and AWFUL lot on a 3rd gen with just those tools.

I started inside and removed my hush panel on the Passenger side, along with the kick panel. There's a few 7MM screws holding in the hush panel ( if equipped ) and 3 phillips head screws holding in the kick.
This gives you access to the ECM and connectors. There are 2-3 connectors on the ECM depending what model it is. Along with those, there are 2 other harnesses that need to be disconnected as well.
Make a note, they will also need to have the pinouts checked and verified and any swaps made to accommodate the new set up. One is a small 4 wire harness, the other goes to a split harness pair of car side connectors. I think this is the C207 ( I will double check )
Here's what it looked like after I pulled the ECM
http://www.blk-wdw.com/87rs/87rs029.jpg

Re: 87 RS V6 to 91 L98 swap
 

Next I started removing the push retainers and screws ( 7 MM ) that hold the passenger side inner fender splash guard in place. This makes life a LOT easier when pulling the ECM harness out of the passenger compartment.
I then removed the hood. I found a rod long enough to hold the front edge up. You want it near the latch in the center. Then I unbolted the hinges from the body stating with the two screws in the front on each side ( 10 MM ) Then carefully removing the rear screw. This is WAY easier with a friend to help, but I did it on my own. Just steady the hood when the bolts come out. It should balance there on it's own.
Next I carefully walk the hinges down the fender mount lips towards the nose until I could tilt the hood forward enough to where it cleared the nose and rested on the ground.

No hood -
http://www.blk-wdw.com/87rs/87rs033.jpg

From here I just started going around the perimeter unbolting things. I like to put the screws/bolts right back where they came out of once the thing they were holding is out. While I pretty much know what goes where at this point just by looking at the bolt or screw.. it saves time searching for them.

Here you can see the removed air cleaner assembly and upper fan mount. Interesting to note, what is underneath the air cleaner, is NOT what I thought I would find. This is very different from the IROC/Z28/RS nose normally. I suspect it's the same as a Sport Coupe. There is just a flat panel. The other nose usually has special ducting the flows the air from the foglight area to the radiator and acts as a shroud to make sure the air is forced through the radiator.
http://www.blk-wdw.com/87rs/87rs030.jpg

Here's a good tip for engine removal and installation. Take the wiper motor assembly out. It gets in the way and is easily damaged. I noted that the bottom of my washer motor shows damage, likely from when this 2.8L was swapped in a few months prior to me buying it. It's 3 10 MM bolts on the outside. Then remove the air duct screen at the windshield base, and gently pry wiper motor arm out of the rubber grommet on the wiper arm assembly.
http://www.blk-wdw.com/87rs/87rs031.jpg

Again everything I have done to this point was with 7 8 10 and 13 MM sockets, flat and phillips screw driver.

Re: 87 RS V6 to 91 L98 swap
 

Did you ever end up completing the swap ??