5.9 swap question
Grab a later 5.9 magnum flexplate that has the balance weight already installed. I believe they started in 97 or 98. My 98 model had the weighted flexplate. This will work with the crank trigger for your fuel injection.
If the torque converter in the 518 has a balance weight on it you'll need to grind it off to make it neutral balance. The la and magnum 360's are balanced differently. Also, if the 518 was behind an LA engine, the converter bolt holes won't be symmetrical and one will be slightly off from the other three. You'll just need to elongate the odd hole with a file to make it work.
You should be able to pick up a weighted magnum flexplate for under 40 bucks at a salvage yard. Look for the big weight. Here's a pic.
One more thing. If the trans isn't electronic, the shifter and kickdown hook up just like a standard 727. You'll just need a 12 volt switch to activate the overdrive.
Hope this helps.....