Table to table relationships using Sync'd data

Projects will be parent. 

So the issue will be if you can change the Key field of the Projects table to be the Job number. Do you have any other relationships in place now in that app where the projects is the Parent record in he relationship?

Yep the projects table is central to our system and has 20+ relationships. 

What i'm playing with at the moment is using Quickbase Actions to create a clone projects table that has job number as key field and then creating a relationship between this and the table holding the QBooks data. 
Its giving me summary data which is a start and my next thought is i may be able to use lookups to pull the original project Id down to sync table (via clone) then use it to link back to original projects table. Not sure if that will work but worth a shot. 

I have used that technique in the past and it has worked for me.  In my case I believe I made a Sync table of a Sync table but with a different Key field.