thats your typical radius arm design, aka y-link. they work better than short arms, but to me are the poorest performing type of long arms.
i made my own 4 link. use MINIMUM of 2", 1/4" wall DOM tube for the lowers. also get some good flex joints, i used Johnny Joints. build it right, and it will be safer than stock. also, the mounting is KEY on unibodies. you can't just weld mounts to the frame. i plated the inside and outside of the frame first.