lightweight flywheel idle issue?

[240six]

I swapped my 98 rb25 240sx with a built 91 300zxtt back in Feb. I just recently received the paperwork from the lein holder and also just found some time to start to try to make it run better. The owner wanted a new project and I think he was having a problem finishing this 300zx. One of the issues was that it was searching for idle. The owner said this was due to the JWT twin pop chargers and the IAA. I studied the the idle line routing and found that he placed the restrictor in the wrong place. I relocated and fixed that problem in 10 minutes. Now it idles just fine.

The second issue. The motor dies as it revs down from high rpm. When at speed and coming to a stop, the rpm drops and drops and drops to zero unless you blip it to idle rpm. I feel this is due to the 10 lb flywheel he installed. I've seen this on other cars and was wondering if anyone here has experienced it and how it was resolved?

Anyway, I really love the way the car drives. It wants to go, but I am holding it back since it still needs to be tuned from the rebuild. The motor was built .40 over with all the good stuff. JWT software, JWT500 turbos. forged pistons, etc should make 400whp an easy reach. Unfortunately, I am scheduled to be sent out of state pretty soon and this project will again be on hold. Before that time, I will try to get some high flow cats and a smog friendly tune done to this so I can at least drive it safely and more importantly get it registered. If by chance anyone in the SoCal area is interested in buying this monster, I am willing to let it go so that it could be enjoyed properly. I'm not putting it up for sale publicly yet since it is not in sellable condition per California standard at the moment. E-mail me if you're interested... junnlen at yahoo dot com.