I've replaced the hose joints on a couple trucks, checked a leftover piece of approved gas hose I got at NAPA for the TF trucks, right at 1.5" ID, and yes it is spendy .... you will not get a 1&1/4" hose over a 1&3/8 tube if it's the correct gas approved hose, there is virtually no flex or give in the stuff, it's a struggle getting the correct size on
Bill