After a bit of tinkering (well alot) I trial fitted the reproduction gasket set i made to a 240z series 1

 

How did you make them? 3d print?

Thanks for the note, it's a combination of a couple of different techniques but printing was involved in one of the steps.

 

If anyone is interested the ebay link is here.

https://www.ebay.co.uk/itm/167047639467

Also comes with a pair of Closed- cell structure EVA foam which is waterproof. 

And should anyone be interested in the ducts themselves

https://www.ebay.co.uk/itm/167065483403