Aligning body work

[Baker819]

I was reading on here how to align the cab and bed. I swapped my step side for a fleetside and the new bedsides seem to stick out 1/2" on both sides. It just doesnt look right. I measured under the cab and bed and repositioned the body to be equal distances from the frame ( side to side ). The front bed panel is also new but the bed floor is from a long bed I cut down. There just doesnt seem to be enough play to suck in the sides an inch on both sides. Any ideas what to do?

I have a 69 c10 swb and I converted it from stepside to fleetside. Thank you