Could always try a Flow Kooler LS water pump.
I use RMI-25 added to my glycol coolant and found it actually lowers temps by 10-15degF
A radiator with 2 rows of 1-1/4” tubes cools the best on my Buick Grand National I bet it would help you with your situation.
I installed my intrepid dual fans using a spare trunk weatherstrip to surround the fan housing perimeter which seals the fans to the rad but also prevents chafing if not installed
1670 1997-2006 LS Gen III/IV Motor water pump
Flowkooler pump 1670 for the LS motor has a CNC machined billet impeller designed with an increased vane count and a reduced plate-to-impeller clearance to achieve greater flow rates, higher head pressure and a more efficient flow than other OEM water pumps. Type II Class II military grade...
flowkoolerwaterpumps.com
I use RMI-25 added to my glycol coolant and found it actually lowers temps by 10-15degF
RMI-25 - Engine Coolant System
Welcome to the official website of Nevada Coolant, LLC, makers of RMI-25. RMI-25 restores the additive package to your antifreeze.
www.rmi25.com
A radiator with 2 rows of 1-1/4” tubes cools the best on my Buick Grand National I bet it would help you with your situation.
I installed my intrepid dual fans using a spare trunk weatherstrip to surround the fan housing perimeter which seals the fans to the rad but also prevents chafing if not installed