Which disc brake assembly

[xx88man]

I'm looking for input from guys that have swapped their drum brakes for a disc brake setup. I currently have drum brakes but I also have disc brake spindles from a 1970 Challenger. Is that the best setup to use or are there advantages to using a setup from a mid-seventies A-body?
It's a '70 Cuda that's going to be driven.

[Skid Row]

I believe the aftermarket disc brake kits bolt up to the drum brake spindles you have, However If you want larger OEM brakes use 73-74 E-Body or 73-76 A Body disc brake spindles with 76-78 B-Body calipers & mounting brackets. The 76-78 B-Body rotors are larger than the original 73-74 E-Body disc  brake rotors.

[Brads70]

 
Stopping fast costs money, how fast do you want to stop? 

[303 Mopar]

www.doctordiff.com has a kit specific for '70 only spindles, and yes they are a one year only spindle. Wheel size is a restriction on rotor and caliper size, so unless you have 17" wheels minimum you will be restricted to what will fit.

I also think rear discs are overrated and unnecessary for most applications, unless you are doing for looks.

[Katfish]

Everything you need to know

https://www.allpar.com/history/mopar/brakes/disc-main.html

1 caveat, Dr Diff sells sleeves to all you to use your small diameter spindles with the later more desirable rotors that are much less expensive.

[xx88man]

Great info. Thanks guys!