could some one give the details on exactly how to mount an external oil cooler above the gear box. Its a KG, 1916 motor, the case has been drilled and taped, and at the moment there is just a loop hose from the pump to the fitting. And should I go RX7 cooler from a wrecker? or a new one from Vintage Veedub for about a billion dollars?

I run the middle sized bugpack one above the gear box. I ran the oil lines out the left side of the engine bay (cut a whole) and then foward to the cooler. The cooler is mounted with the leading edge using alum angle just at the front curve (where the floor curves down towards the torsion bar tubes) and the back is held using threaded rod hung from above. The cooler sits at about 45 degrees from vertical.

Get a RX7 one from the wreckers... mount it all find out it is split or contaminated then get it welded and try to get it cleaned.... yeah i suspose it about the same cost.
If you do get a S/H one make sure its noty full of engine blow metal other wise you will be wasting your time.

I agree buy a new one or wait till you can, if the s/h cooler has a problem its cheeper to buy a new cooler than re build an engine.

Somtime theres no substitute for new parts, peopl have to learn the hard and costly way.

The other thing to look at is why its running hot in the first place.

Good luck

in brisbane i run a cover on mine for the winter insulate the lines as in winter, (even in hard driving) th etemp doesn't go over 70 degrees. I do remove it autocross etc

I thought a 1916 will run hot without an external oil cooler regardless, cos of its bigger capasity. assuming all tin is fine and jetted right she wont run hot? even on the freeway?