Need some suggestions on how to correct this gap.

look at all the advice --- sift out the parts you need ,then sneak up on your solution(a little at a time)lots of measuring and good luck...

 

Thank you for all the advise, I'll be heading out to garage in a bit and I'll see what I can come up with.

 

Just a flow up, I was able to borrow a porta power this weekend and was able to correct the gap issue. Thanks for all the help.