"Let me close with a question: What are the implicatins of NOT adhering to the cab floor to top-of-frame clearances of 1.83 - 1.89 in the front and .76 - .82 in the rear? I know I can achieve it, but I am curious about the consequences of not achieving it." (Pat)
I would contact the manufacturer of the frame. From what I saw in person, they went to great trobleto design this frame for our trucks.
Since their frame does not call for shackles, they will know the answer to your question.
There are three reference points in a frame (their custom frame and our original frames) which must come together for sucessfulmounting of the cab and front clip.
They are:
The distance from the bottom of the rear cab supports and the frame, as well as the distance from the bottom of the front cab supports and the frame, and the corresponding position of where the stock radiator support meets the front crossmember.
The custom frame may well have completely different specs than a stock frame, especially since there are no shackles used with their design.
I would be shocked and very disappointed if they can't provide you with very specific recommendations right off the top of their head.
