SRS. ill price it out and see what it will be.
we need to box the frame as far forward as we can too. if you dont want to take the cab off, we could do it on a lift. if not the back half needs to be boxed 100%. to stiffen the flex up and to make good solid mounting points for the links and brackets. Might even make some X braces as long as they clear the drive shaft to keep the side to side deflection down on a launch.
but the 4 link is the best bet. you can set the angles so when it loads on a launch it works to pivot back and transfer the weight back much harder than any leaf sprung thing will ever do. and its fully adjustable, side to side, front to back, wheel base, pinion angle, caster angle…