So what is this truck going to be used for?
Your current plan sounds more like a car engine than a 4x4.
Holly is a great carb, just don't get bouncy(rutted fire road or sand dunes) or at any steep angles/hill climbs. That Holly will barf into your intake. Q-jet is the best carb for off-raod. I ran the Edelbrock 1901 for years on my 350.
Don't get me worng the truck will be fun to drive for sure, just some sacrafices to think about, but again depends on what the truck will be used for.
My .02c