^^ exactly what blaaster said about figuring swinger length.
As far as those shocks working... The rear shock will work great with KOR bushings.
The fronts are a little different story. Stock blaster shocks are 14.5in from eye to eye and the 450 shocks are about 16.75 so theres no way they will bolt up. But since you were talking about aftermarket A-arms, some a-arms are made to use stock shock lengths and others are made for longer shocks. I'm not sure about how long of a shock they might use though so you'd have to check. (I know some are make for 16in) It might be a safer bet to pick out/get the set of a-arms you want and then try and find a pair of shocks that'll work for those arms.