Electric water pump - configuration of heater hoses

I'd start with the Meziere website

"There used to be" a device to tap into a lower hose for block heater

1-1/2" Lower Radiator Hose Connector for Kat's Heaters Circulating Tank Heaters Kats Heater

https://shell7.tdl.com/~jags/Pages/Parts_DATZ_Hose-Splice-Kit.html

Found this

AutoMeter Radiator Hose Adapters 2283