70 C-10 Disk Brake Conversion Question

[matthamby]

I have a 70 Chevy C-10. I was looking at doing the front suspension swap from a mid 80's C-10. I was also thinking of getting a modern rear axle (from something in the 2000's) that has rear disk brakes & 3.42 gearing - I will be using a 93 5.7 ltr engine (it will eventually push 400+/- HP) and a 700r4 tranny. I wanted to keep the 6 lug bolt pattern, as I want to use some 18" wheels and tires from a 2013 Silverado. I have found rotors that swaps the front to 6 lug (CPP Rotors Link). My biggest concern is the wheel mount to wheel mount measurements from the front end to the newer rear end. I have looked and looked - I can't find a definitive answer to this. At worst case I could use adapters to get the correct spacing - if the rear end won't be too wide!

Any help with this would be great also!