The 87 had a hydraulic prop rod (left side) from the factory, as opposed to the scissors prop on the right side for 86 and earlier. What's modded about yours? I've installed a later hydraulic rod on my 86, so I might be able to help if I know what's different about your new one.
The thing you have to do is remove the old rod and support bracket, and the new one goes a LOT further down in the engine bay - I've circled the two bolts that it connects to, and they're on the frame. I had to cut a small piece out of the brace that runs from the frame to the fender just in front of the wheel well, but it still screws back in place nicely. IIRC, the brace's bolt is the rearmost of the two you use. You may also have to bend the bracket that holds those steel lines to the frame, but just a tiny bit. The prop rod goes underneath the lines.
I can try to take some more pictures if you want, but access is limited in that area and I probably won't get anything better than I already have.
Good luck, and any help I can give is yours.