5.9 Magnum FI cam upgrade

When you have the "beer keg" intake off, there are a few important mod's. Most important is that the sheet-metal bottom cover blows the gasket and leaks, sucking in oil. You can get a thick aluminum plate replacement on ebay ~$50. For better high rpm, some people cut the internal intake runners shorter. There are plans on ebay, or just wing it.

I haven't heard of anyone hacking the Mopar computer. It might be easier to use a proven solution like a GM computer. Howell Engineering does that and might be able to work with your Magnum. Another choice might be a Holley Commander 950. I got the ECU alone for just $120 on ebay. It uses GM type connectors and I may wire to a Magnum engine harness I have someday. It might also run fine with the stock computer. I suspect the cam would matter more if using alpha-N control. Mopar uses Pman and rpm, so if the displacement doesn't change, it might be close enough that the O2 feedback tweaks it in. If a really wild cam, the Pman signal doesn't well correlate to air flow, so may cause problems. Some hot rod kits add electronics to bugger with the Pman signal, but I don't know if there are any for Mopars.