Lowered trucks and rear tire to wheel tub clearance.

[Slik66]

I am building a 66 short bed and have 3" drop spindles and 1" lowered springs for the front. I have 4" lowering springs for the rear but may need to do 5 or 6" springs in rear....I also have a C notch kit.

My question is: Do any of you lowered guys have issues with the rear tires hitting the rear wheel tubs while driving?

I will have to do a mini tub because my rear wheels are 305/30/22's and they are a little taller than the normal tire for this truck so that's why i'm concerned with bottoming out on the tubs.