TH400 TO 4L80E Conversion

[Accelo]

Only the original style, push in fittings, or the aftermarket ones with the AN connections are available. If they make them I couldn't find them.
Not all 4l60E take the same rear fitting, later ones take the extended ones.
The aftermarket hydraulic tubing flair tool will put the push connection into the tubing if you really want to go steel lines. Does your radiator take 3/8" or 5/16" tubing?
The 4L80E transmission takes 3/8" line. All the early radiators have the 5/16" fittings in them that match up with THM 350, 400 and Powerglides.