I just installed set of Hooker long tube headers on a 78 F100. Hooker’s instructions stated the frame cross member would have to removed then reinstalled after headers were on. It’s the first cross member behind past the oil pan (there’s a second crossmember under the transmission. The problem is with the headers on the cross member won’t go back on. The header tubes on the passenger side block being able to put it back. Anyone run into this and if so what was your fix. The truck is 2 wheel drive.

Appreciate the response. What you’ve recommended is the path I ended up taking. I removed the cross member and installed the headers. After installing the headers I put the cross member up to the headers as close as to where it was supposed to be as possible and marked it where it would need to be cut. Took the cross member to a local steel shop and he did a good smooth cut out. Wasn’t much and the cross member slid right into place.