If I get new Rocker Arms and Shafts can they be assembled without any Machine Shop work required? Thanks

  

In most cases, yes. If you're changing rocker ratios, installing a high-lift cam, milling the heads/zero-decking the block, the rocker stands might need to be shimmed or cut to correct rocker-arm-to-valve geometry. Read Ted Eaton's "Rocker Arm Geometry" article. If you choose to pressurize the rocker assemblies, they are normally disassembled and oil grooves cut in the shafts. You might want to buy an adjustable push rod to determine the length of push rods you'll need, if the geometry needs to be corrected.  

You will need to check the rocker arm to shaft clearance.  I like 0.002”.  The factory specification is 0.002”-0.004” with the wear limit being 0.006”.  I find considerable variances in the new rocker arm shaft diameters so be sure to check those clearances before assembling.  If the clearance is too loose, then look for a different combination of parts; either more rockers and/or different shafts.  Installing bushings in the rocker arms is an option for tightening up the clearances when they are on the loose side.

As Jeff brings up, check the rocker arm geometry.  Valve jobs and/or replacing the valves with shorter/longer stems can alter the geometry on the Ford Y.

Lorena, Texas (South of Waco)

Thank You Ted