Big Brake Conversion Questions

[66 C10 383]

I'm building a 66 C10 and plan on swapping in an 81 crossmember. Before ordering my drop spindles, I'm wondering which 13" brake setup to go with. I plan on it being mostly/eventually a daily driver and my concerns are durability and replacement parts.

C5 Corvette brakes - I have these from a project I abandoned and never used. I'd more than likely get the 4.75 spaced hubs so I can run stock Vette calipers and rotors. The Vette rotors are the same 1.25" thickness as the HD truck setup but my main concern with these, is the caliper stout enough to adequetely stop a full size truck at normal highway speeds? I'd say they gotta be better than the stock drums

McGaughys 13" 2.5 Drop brakes - This setup uses the truck dual piston caliper. The truck caliper uses 2 52mm pistons vs the Vettes 4xmm (?) pistons. Also, this setup uses either the 5x5 or the 5x4.75 bolt spacing of your choice. Does the 4.75 use a stock Vette rotor making replacement as easy as going down to the local parts house? Where (besides McGaughys) would you be able to find a 5x5 13" rotor?

I like being able to get replacement parts locally if repairs are needed.

Is there any disadvantage to running the 4.75 bolt spacing over the more common 5x5 as far as durability goes? I'll be running 17" wheels with the good billet adapters so I can go with either bolt spacing.

Thanks

Doug