35 years ago I owned an auto parts store.  At the time there were companies that rebuilt the rocker arms on these engines.  Is that still done?  Is it cost prohibitive?  I have some used rocker arms that the shafts are galled from likely lack of maintenance.  I would like to have them rebuilt and keep in stock as I own six 1955-1957 Y block vehicles.

Rocker Arms Unlimited in Redding, CA can rebuild them. You can buy new shafts from several sources. John Mummert (ford-y-block.com) sells components and complete assemblies. Tim McMaster (yblockguy.com) has a video on rebuilding rocker assemblies that includes "pressurizing" them. 

thank you!  I will look at Tim's video.  I use him for my engines.  He is great!

He wasn't/isn't interested in building mine, possibly because I've already acquired most of the replacement parts (all quality including parts he has used on other builds). 

What parts did you buy?   I've seen the shafts, what else is needed?

Mummert (SI) stock-size stainless valves
Mummert Stroker H-Beam rods
Clevite bi-metal Buick rod bearings (also from Mummert)
Racetec (Autotec) 3.825 flat-top forged pistons
Sealed Power ,010 main bearings
Hastings metric rings (1.5, 1.5, 3.0 mm)
PAC 1286 beehive valve springs, retainers, & 10-degree locks
Holley 1850 Street Avenger 570 carburetor
CRT tach-drive distributor
Sanderson Tbird ceramic-coated headers
Casco water pump
Powermaster PowerGen alternator
Carter M6905 fuel pump
Howard's Cams 292002-10 cam
Verne Schumann's Durabond cam bearings with center bearing grooved on back side
ECZ-G (non-posted) heads were ported by me, decked .013, hardened exhaust seats & bronze valve-guide liners installed, 3-angle valve job (30, 45, 60/w intake valves back-cut 30 degrees), guides cut for ,500-lift cam & Comp Cams Viton positive seals 
ECZ-B intake ported by Ted Eaton
Dampener rebuilt by Damper Dudes
Rollmaster timing chain set
1.60-ratio rocker assemblies purchased from "Richard" on this forum (probably sourced from Rocker Arms Unlimited, not aluminum Harland Sharp)

In other words, there's not much left to be purchased.