Thats just it Keith, the factory master cylinder is this ridiculously tiny thing that looks like it was made for a Ford Fiesta! The one for the Silverado appears perhaps three times the capacity.
As far as the argument about leaks, well I dont claim to have particular knowledge and experience in the area of dual-brake boosters, but it defies common sense that a leak in a single or dual system would have any different effect. A vacuum leak should just mean it would be hard to brake but the hydraulics would still work.
Well folks, if I crash and total the truck, I guess we’ll have more definitive answers on this topic!
Thanks again all.