I’m not here to tell you that this is the way to do your radiator hoses. I’m here to tell you that this worked for me and my setup.
Remember as you read my description that I set my engine forward 3 1/2″+/-from the usual “1” setback” than most adapter plates are manufactured for. I’m using the truck water pump so I have the 1-1/4″ water neck. The radiator is the OEM V8 radiator for the ’66, which has a 1-3/4″ connection.
Upper:
Dayco 71989 1-1/4″ Radiator hose (standard 5.3L truck hose) to 1-1/4″ to 1-1/2″ Aluminum billet hose barb coupler to Gates 26391 1-3/4″ to 1-1/2″ reducer to Dayco 70155 1-3/4″
I removed the 90° radiator end off the 71989 and the 90° bend from the 70155. Using the billet coupler and the Gates 26391 I connected the remaining 71989 to the 70155 end. It look s a little odd, but successfully combined the two to have a working upper radiator hose.
Lower:
I used a Spectre 4939 swivel thermostat housing for the lower inlet because the OEM truck inlet didn’t allow for a good routing of the lower hose. On the water neck end, I used another Gates 26391 (1-3/4″-1-1/2″ reducer). This allowed me to use a Dayco 81301 (1-3/4″) 10″ flex hose to connect to the lower 1-3/4″ radiator neck.
