door to fender gap too wide HELP please

[Dads 68 GMC]

Hey, its been a long time since I have been on here. I finally got some time to work on the 68 gmc 4x4.I painted the doors & fenders last week,installed them & the gap is too wide on the bottom,1/2'' on one side & 3/4'' on the other. the frame & radiator support are original & the fenders are Goodmark. I installed an (ENERGY) polyurethane body kit. I took the front mounts out & put an 1/8'' rubber piece instead,before I did this the gap was wider yet. I wonder if I need to raise the front of the cab, what do you guys think?
I think the cab was off of a 71 2wd if that makes a difference. any help is greatly appreciated,Philip