I just went thru this. No there is no kit available. To many variables on a G bodys to offer a kit. The reason I say this is because there are variations on trunk hinge support from model to model. This prevents you from using a typical 36 in tub kit. Take a closer look at the taper in the stcok inner wheel wells. It would make it dificult. I ended up steching the stockers and tweeaking the stock trunk hinge supports slightly for clearance.
I just wanted to take advantage of the notch on my frame. I have a small amount of rust on my inner where it meets the trunk floor which is really common, was hoping to remove that rust and add some tub, then I should be able to tuck a good size tire with a low ride height...Ill search for some pics of your wheel well mods, im certain you have taken some!! Thanks for the info!