Did lots of measuring, ordered a part. got part, installed part. Part hit another part it shouldn't. Felt sad,had a beer, worked out the part the part was bolted to was too close to the other parts because I was using a tool to hold up the part that didn't have the usual part in the right place to hold the part.
Turns out when the part is in the place it should be when the part that holds up the part is in place, the part that was hitting the other parts doesn't hit the other part.