First of all have fun with it. 2nd, take the crossfire (which should only have come on the '84 model) and throw it away. Either move up to a tuned port or cheaper and easier method is to just carb it with a new Edelbrock from Summit tuned to your motor... turn the key and hear it purr. I'm building an ls with fuel injection now, but with that L98 you're working with, you will not see a major gain... just a lighter wallet. Everything is more expensive from kick down cables to throttle and mounts. Carb-it! 3rd... your trailing arms somewhat limit you in width of tire... cut the bolts out that hold them to the rear bearing carrier and heat shield (otherwise you will have to dismantle everything). Buy new grade 8 bolts and move the trailing arms inward towards the pumpkin in order to give you more room for more meat... (She likes more meat!) This will also help with the narrower frame that you are dealing with for mounting locations. If you can fit the cradle as a whole that would be sweet... includes motor mounts and all. The geometry of the front suspension is more detailed than most think... sure you can adjust the camber with shims, but I'd prefer not to look at any more than necessary. Try not to re-invent the wheel as many do with the C4 technology. Yes it is dated today (particularly the engine) but the suspension is a great candidate for a hot rod fusion. The beauty of this is that you have the '84-'86 which is about an inch narrower. I have a setup sitting outside for an F1 project down the road. Just finished a '57 chevy p/u using a crown vic front suspension. Worked great but was very wide and did not leave much/any backspacing on the front wheels after being built to get around the big calipers. In hindsight I would have donated my C4 stuff to the cause just due to the width alone. GOOD LUCK to you! stiffen up that chassis as well... it was designed to twist and flex with the straight axles... the C4 stuff was designed to be bolted to a Very rigid chassis... Particularly the Aluminum rear batwing... be sure you're rigid here.
Wow... that ran on... hope I threw something useful your way.