2001 Tahoe Fuel Tank

[oneputt0731]

Started to replace defective fuel pump and found the lock ring badly rusted. Needless to say the "tangs" on the tank that the lock ring locks on are rusted beyond use. The tank is fine otherwise. Is there any possible way to replace/repair the "tangs"? GM parts sites all say tank is discontinued and if were in stock $550 (for a plastic tank). With 200k miles I am open to any suggestions.