Besides going to a billet electric pump, I've seen adapters that allow a big block Chevy pump to be installed on an LS.
https://www.jegs.com/i/Moroso/710/63...QaAmvPEALw_wcB
I found a billet water pump for the LS that moves the thermostat to the top, but it's quite pricy. Comes in black or silver.