rear suspension options?

What are you guys using to keep your rear end suspension from hopping and moving around.

i just put bigger rims and tires on.

I down shifted the other day got a violent reaction from the rear axle, got a enough movement in the leaf spring that the tires touched the body and bend some sheet metal up. luckily it didnt ruin my tires and i dont have a nice paint job yet...:D

Normally when i down shift at higher RPM to engine brake, the rear tires would skid, well these bigger street slicks dont want to skid or slide.

ive tried the cheap bolt on traction bars no luck there.

what are you guys using? does someone make a kit out there? i could only find one on the internet, found a slide a link traction bar on summit racing that fits my application.

1970 dodge dart with the 8-3/4 rear end. its also has a rubber differential bump stop.

what do they call it, 4 link? because there is two pivots on each side?

would it be pretty easy to make something?