Ed, your pics are taken up so close we can’t tell what we are looking at.

These are slightly better pictures showing the gap on the left side. The firewall with the cowl installed matches up the four holes pretty well where the bracing bolts go through all four pieces of metal. I will try to get a picture of this tomorrow. 

Last edited by Mochaman (1/03/2023 8:37 PM)

I would make sure the doors installed on the cowl match up to the rockers.  That will determine the position of the cowl.  Perhaps firewall can move forward?  I would want to be sure the doors wound up in the right relationship with the rockers.  Then mock up the fenders in relation to the doors, then be sure inner fenders are in correct relation to the fenders.  The top of the cowl must align with the top of the fenders.  Quarter panels then must be aligned to the doors.
After it's all said and done, if the outer sheetmetal doesn't line up, you have a pile of garbage.  The stuff underneath only has to align to the jig's suspension pick-up points.
If you need dimensions off a fairly unmolested convertible, I can help...

checkout Peterson Restoration on Utube and search for 65 mustang fastback rebuild.
he is assembling all new sheet metal like you and i think episode 3 is dealing with front shock tower panels 
hope it has some help/insight

good luck
mark

Thanks mjacobs. I will have a look. I have been going over the Joe Daddy's Brooklyn Pony series. He is doing same thing but sort of skipped past some import info that I needed.