[oldasi]

joeydurango, ........... Just happened to be sitting enjoying a cold one looking at the front wheels and thinking exactly what you mentioned in your reply, believe that was the problem, wheels not straight. Now the issue of the different distances measuring rear wheels within fender wells I think can be corrected when box is repositioned to get distance behind cab to front of box equal, one corner is 1/2" other is 1 3/4" .
streetrodchev, .......... yes, did that and corner to corner X within 1/2", length end to end the same, both sides as side to side is 1/2" difference. Feel that these will correct them selves when I correct gap behind cab, cab to front of box.
One issue I don't understand is the stake pocket dimensions, 1 dimension is 41 1/4" as spec, other is 58 1/4" vs 52" as spec for 104" box ???
thanks to all for commenting, ......... cheers