Reply to cat_d7_17a:
I have called and called trying to find a turbo with no luck. Would it hurt to use a D339 D7E turbo instead? The only difference is 20 more horsepower and 100 more rpm isn't it? I photo-tached my 17a on the drive shaft with the clutch engaged and in neutral and it read 1360rpm with no load. In theory the 160hp d7e turbo should be running the same boost and airflow as a 17a with the same cubic inches and rpm right? I don't want to melt anything since it only has 200 hours on new sleeves and pistons and heads. Any input would really be appreciated.
You won't melt anything particularly if you find a similarly mapped alternate turbo. You need to determine what the map for the old turbo is/was. Once you've done that, it's pretty easy to go online and find a turbo with a similar map. From that, it's just a matter of making sure you can bolt it up and plumb it. I added a turbo to my lawnmower (JD430) and basically just made up a transition piece from the original exhaust manifold flange to the turbine flange. The impeller end was easier because it was just flexible pipes but if you need a flange on that side too, just use the same approach.
Plumb the oil feed back in and hook up an oil drain back to the original drain inlet to the oil pan or lower block. Make sure the oil drain is at least the same diameter as the outlet hole on the turbo and you'll be good to go.
Put this "https://www.google.com/search?client=safari&rls=en&q=turbocharger+maps+explained&ie=UTF-8&oe=UTF-8" into your browser and you'll see a bunch of links explaining it.