How straight is straight on a classic mustang?

[mungus]

Took advantage of the old girl being on my swanky new rotisserie tonight. Just measured up the chassis using the well known factory crash sheet. Most of the distances were spot on, less than 1 mm out, all except 2 that was!

One being one of the front diagonals (RH forward upper arm mount hole to front steering box mount), was out by 7mm and one of the rear diagonals (rear rail forward hole to opposite rear leaf rear hanger hole, vertically aligned to a datum of course), was out by around 13mm. (Other side was spot on).

All this was just done by hand with a builders tape, so hardly laser accurate, although I did check them many times.
I figured it was worth checking while the old girls laid bare etc.

From reading around the mustang webs it seems the factory was a bit rough on such dimensions, so just how straight were they, and just how fussy do we get on average?

The front diagonal is bigger than the stated distance, so not the result of been wacked in. And at 7mm I'm thinking it might be acceptable. Perhaps the export braces and crossmember might even pull that in a bit.

But what about the rear one? Is 1/2" excessive in Mustang land? Door gaps looked OK and the rear quarters are straight, soooo what's the view? Worth getting it pulled straight, or live with my Metuchen's imperfection?

Views appreciated...

[xpconnor]

I'm not really the most knowledgable person to be answering this but I would have the car on all four wheels or a jig to be taking the measurements. Someone like Kerry will confirm but they can twist a lot up on the spit.

[mungus]

True, I thought of that too, however being a fastback I imagined it wouldn't twist up as badly. Perhaps others will know?
In any case I'm thinking it's not excessive and I can recheck it at various times along the way.
I must admit it does flex around a bit and the structure is torsionally weaker than I imagined!
I can see why people fit the rail braces now, and I'm even considering doing that.
At least the cabin section would have some strength in a ding and allow the suspension to work without flexing every seam in the car!

Standing by for more...

[hybrid]

As stated, measuring on a rotisserie is not a good idea. These cars flex a lot when they are held only on the ends.

[mungus]

Fair enough. I won't take much notice of what I've just seen and wait until she's down on the ground again.