Look into a frame swap. Buy a complete Jag S-type (preferably wrecked), cut off the body and drop your Mopar body and sheetmetal right on top of the Jag chassis. The track width on both as well as wheelbase is fairly close. Check out 'Frame Swap Faction' of FB.
thank you for that info. i have a s type jag i was tinking of putting all into rhe plymouth.i presently have the front and rear suspension from a xjs jag built in.i have outboard rear brakes i would like to have the inboard brakes.thanks again.