How wide can I go?

I haven't been on here in a long time, and i am actually going to finish doing a v8 swap in my mazda. But I am lost to one thing right now on my list o-shit to do. With a set of escalade wheels...how wide a tire can I go? For now im going stock rear end until I get rear-end built for more power...im just putting a 305 with some bolts ons for now. But I want to be able to go as wide a tire as I can for now on the escalades...any info????

I ran 205/40/17 on my 88 b2200 but you should be able to run a 215/40/17 depending on how low you are.

Anyone know the perfect combination as far as spacing and width? bodydropped 87 b2000.