I'm restoring an Australian 1970 Mk1 Twin cam. I need a modern paint code or formula for color J, Hot Orange.

Where are you located ?
Is the car still in tack with the original colour any where ?
If you have this ,then you can take the panel to a paint suppler of automotive paint and they can computer match it.
What you will find is the paint of the 70s era you speak of had a lot of lead content and todays paint has no lead so
no formulation without a good sample is possible.
I am restoring a 1962 MK1 Cortina in my workshop and this is what we did. 

Thanks for your reply. I'm in NZ. The car had been repainted white years ago . I have stripped it to bare metal and there is no orange left apart from a small section under the boot hinge but can't guarantee that this is the true and original orange colour. I will try your suggestion..Thanks
I also need the black rubber hoses that run from the master cylinders to the reservoir bottle. The originals had a yellow strip on the hose. does anyone know where i can get some ?

http://www.ebay.co.uk/itm/Mk1-Escort-TwinCam-RS1600-Lotus-Cortina-Girling-Yellow-line-Servo-Vacume-Hose-/181151166106?pt=LH_DefaultDomain_3&hash=item2a2d736e9a 

Any decent paint shop will have a code book that will tell them exactly how to mix any colour, you need to tell them the year, brand (ford), code and colour name if you have it. as has been said the old paints did contain lead but the paints are pretty much spot on if you get a good paint mixer, original paint on a car will be faded to hell after 40 years of aussie sunshine

Hi Troppo ,
You are right with a decent work shop should or may have held on to the old formula books as I have,
However The paints of today are not pretty well spot on as they have no lead and the modern formulations by computer has not made the allowance for the lack of lead content, there is a major variant. I have been through this with many restorations to match the precise toning of yester year.