I don't see a web site for a company or product line called New Generation though I see some branded as such for sale on Amazon and other places. Do you have a website or catalog link for them?
I see this site for AMS Automotive comes up
http://www.amsautomotive.com/new-clutch-kits. They have clutches listed but all the single mass clutches and flywheels seem to be for 1 1/8" input shafts whereas the 1 1/4" input setups are listed as dual mass. It's my understanding the diesel ZF5 is 1 1/4" input.
I'm going to see if South Bend can get me a clutch setup for this combination, maybe someone knows of another off the shelf option though. I definitely do not want a dual mass flywheel though so that leaves the excessively expensive stock replacement options for an '87 out. Hopefully someone offers a single mass setup for this combination.