I verified that Rans wanted me to mount a 1" hose on the 5/8ths" leg at the source and destination coolant hose T's and then mount the hose on the 1" legs on the firewall connections. I was uncomfortable with this as I am concerned that over time the 1" hose on those 5/8th" legs would eventually leak. I instead purchased metal automotive metal cooling system 5/8" T's and installed 5/8" cooling system hoses.