Overheating at rest

[blown5.5]

Agghhh that age old problem of overheating. If I sit for more than 3-4 minutes in warm weather the temp gauge starts it's migration to meltdown. While this would appear to be an easy problem to fix, it's solution has eluded me for over two years. Currently the car is running a FoMoCo 8500-C 3 row aluminum radiator (3 times the surface of the original), a Meziere 55GPM Electric Water Pump, a Black Magic 15in (2800CFM) fan, and Propylene Glycol Coolant (far better heat transfer). The fact that it occurs at rest usually points to a flow problem (air or water), however with the current setup it probably flows more than the stock items did at 40MPH. I don't believe there's an obstruction in the block as it was set up professionally (DSS short block). The Glycol is not contaminated as the block has been water free since it was set up. I installed a 140 Amp alternator and oversize battery, so the juice to the fan and water pump doesn't drop as the engine idles. I have tried several different combo's for thermostat (180 - 160 - none) and will try a restrictor plate as soon as Jeg's gets around to sending it. The only other non-stock item is the heater is disconnected. The bypass hose doesn't look kinked, but I'm having one made up that is a perfect half circle of the proper size. I'm hoping one of you can think of something I've overlooked. It's really embarrassing to sit in line for registration at the drags and have to constantly fire up and shut down the engine while moving forward, but it's either that or push the car forward which is worse -- Aggghhh