Is your 55 a big truck, like a 1 ton or bigger? The 68" wheel track sounds awfully wide to me.

I did a 54 Dodge 1/2 ton with a FMJ clip (62" track width) and the tires were right at the fender edge. (2nd picture)

I'm doing a 49 Dodge truck on a Dakota 4x4 chassis and the tires are right at the edge of the fenders. I'm not buying the track with on a 55 is that much wider then the 49 is. The cab was different in the length of the roof due to the curved windshield, but the width was the same. (1st picture)