Don't fall into the trap of believing you need to change your front suspension, especially if your buddy is a Chevy guy. (I sometimes actually feel sorry for those guys)
The Mopar front and rear suspensions have better geometry and hardware than the factory GM and Fords of that era. With the correct combination of parts it's more than capable of holding it's own. Google Green Brick if you want to amuse yourself.
It is VERY common to swap to 73-76 A body BBP discs on the earlier cars. My 68 has them and it looks like your Swinger does too. Another way to tell what K member you have is to check the motor mounts. 73-76 have spool mounts and the earlier ones have biscuits. Yours probably retained the 70 K.
