Need advice on suspension and brake upgrades

I'm in the same boat, sort of, but mine is a 73 Duster w factory drum brakes & the small 4" bolt pattern wheels. I know my rear is a 7 1/4" & won't hold up with any kind of power thrown at it, but your Barracuda MAY have an 8 3/4" rear from the factory which is plenty strong for your 480HP engine. 8 3/4" rears have a round center, NO rear cover & are removed from the front of the housing. The 7 1/4" has a 9-bolt cover & will not last long with your engine. I'm going with the Wilwood disc conversion kit for my car. (I've had three so far & like them very much) If you swap to disc, you will probably have to change your master cylinder over, & maybe rear wheel cylinders with a smaller bore. I believe with some Wilwood kits, you use your factory spindles & everything, so you won't need to buy all the extra components. As far as Hotchkiss components, I have their lowering kit on my 2000 Dakota (front & rear springs, & Bilstein shocks) They have been on the truck for over 15 years & have had ZERO problems with their products. Sway bars WILL make a difference, just remember, don't tighten ANY suspension pieces until the full weight of the car is on the ground. Good luck.