big price difference to get the steam port!
here is the upper rad hose coupler with steam port I used on last LS swap:
https://www.amazon.ca/gp/product/B0BKRS2GPN/
1-1/4 inch Radiator Hose Barb Adapter with 1/8" NPT Port is description. Check dimensions as some listings use that description but the coupler is much smaller OD than 1 1/4
and the 1/8 NPT 1/4" hose barb :
https://www.amazon.ca/gp/product/B06XS164TV/
I do think a rad supplier for LS swap into a specific vehicle should be able to specify hoses that fit, but if you need to cobble rad hoses grab the hoses from your swap donner vehicle and some 1-1/4 and 1-1/2 hose couplers without the steam vent.