Welcome to the forum! As Moparmarks wrote, everything will fit, but there are conditions.
1971-1974 Chargers, Roadrunners, and Satellites are all essentially the same and lots of parts will interchange between them, but they also have some unique parts that won't. Also, there's differences between what will fit on a pre-73 car and 73 and later cars. And worse, there's differences within the 73 model year in terms of suspension components, which makes life kinda tricky for us.
And as a BTW, there are also E-body and C body parts that can fit our cars as well. I mention all this not to alarm you, but to let you know you may have options that will lower the price of parts.
General rule of thumb is most all interior components will interchange between 71-74 Roadrunners, Chargers, and Satellites (except for the rear lower quarter covers on 74 cars being different and some Charger sail panels being different). And by interchange, I mean they will fit but the styles/appearances may change.
Most all the sheet metal interchanges between Roadrunners and Satellites if they are 71/72 or 73/74, but not between those two groups.
All the suspension components interchange within 71-72 and 73-74 models, but not between them. And some 73 cars have 74 suspensions.
Best thing to do is just post any specific parts questions on here and someone will have the answer for you. ;)
aboard!
