Got it! clamped it between my BIG back rivet plate and a board with the spacer under it held in place with a couple of holes pinned by small pieces of rivets. Next I took a sharp edged board and clamped it on and then beat on it a little with a hammer.
Put it all back together and found the F638 pieces that go in there. They slide right in now. The gap doesn't appear to be much when looking at it but the piece just pops right in. I'm happy!
JohnR
RV-7A - Fuselage - SOLD, just not supposed to be
Numbers 6:24 - The LORD bless thee, and keep thee