[_Ogre]

I'd try another header or manifold before using 4 steering knuckles. Way to many points of failure in your setup. Plus the heat will cook the grease out. You need to step back and look at the overall design of your truck; steering and brakes should be top priority, not an afterthought. If cast iron manifolds eliminate 2 knuckles and both bearings at the cost of 2% of your power, use the manifolds.
You are designing a vehicle that I wouldn't want on the same roads I use. My 58 TRUK uses 2 steering knuckles, I can remove all the set screws and nothing happens. I have to remove the 4 column bolts before a failure will occur.