Well you have yourself a fine kettle of fish. Been there, done that, don't want to do it that way again
The rubber hose is:
Part # 28 on page 1 & 2 of Group 13 - TC-37F Parts Catalog.
1-5/8" ID x 2-3/8" long 1 Ply Radiator Outlet
Order 2-3/8" from bulk hose part # 407 005 R1
This hose is available in bult at any NAPA or Auto Parts Supply store. There may be a cutting fee. Make sure you do not get the stuff with the wire core - mess is fine, core is a pain in the posterior.
Next PITP is putting it on.
To replace this hose you first must remove the elbol-
Item # 26 Part # 251 430 R2 Elbow, Water Inlet
Neat thing about removing this particular part, is that you have to remove the Mag to get to it
Like I said, been there done that.
Make sure when you remove the mag, that you use a grease pencil, a parts marking pen or even white out to mark the position of the mag. That way, you do not lose your timing - DON"T ASK
If you take your time, it really isn't all that difficult. Just pay attention to where the mag is positioned.