The 427 Ford uses what seems like a very simple rocker shaft arrangement. The stock setup has a hollow shaft supported with four stands. The six inner rockers are kept apart with three light springs. The outer rockers are retained with a wavy washer, a washer and a cotter pin. The whole assembly is bolted to the head with four bolts.
There are different head/intake styles; Low, Medium and High-Rise and Tunnel-Port. To go along with each head type there are three sizes of support stands. The High-Riser heads used a short rocker stand (C3AE-6531-A). Since Higher-Rise, Medium-Rise and Tunnel-Port heads had bigger valves spaced slightly further apart than standard heads, they used .120-inch wider rocker stands. The Medium-Rise/Tunnel-Port stand is C5AZ-6531-A; the Low-Rise used the same stand as the 390 and 428. This was the thinner stand, C5AE-6531-B, but it is the same height as all but the High-Rise.
If you are building a Medium-Rise head you want to be carefull not to use the more common 390 and 428 stand which is the thinner part. Since all the rocker arms are the same width it will alter the rocker arm to valve relationship.
There are only two types of rocker arms, adjustable and not. The adjustable has a 1.76:1 ratio and the non adjustable has a 1.73:1. The larger ratio arm is the prefered choice since it will open the valve further and faster. Both are made from cast iron and have the same width.
Things I learned the hard way
My first engine was delivered to me complete and was a great teaching aid as to how not to build a 427 Ford.
Rocker Shaft Orientation:
The rocker shafts have a small oil hole that needs to point down. The hole provides oil to the rocker arm and if the hole is up like mine were the rockers will sieze. I have no idea why the hole is only on the bottom, it seems to me that it would be a good idea to have a hole in the top also so that the shaft could be installed either way. Some after market shafts have two dimples in the edge of the shaft. This is a good way to check the oil hole location after installing the rockers but before bolting down the assembly.
Rocker Stand Orientation:
The rocker stands all have a oil passage in the base. There is one oil passage in each head. The oil passage in the stand needs to be aligned over the oil passage hole in the head. Unfortunately even though all the stands have the passage, it is possible to install the stands backwards so that the passages do not allign. If this is done all the rockers will sieze. Each of the rocker stands has a clamping split. As long as the split is facing the exhaust side the oil holes will be aligned.
Rocker Bolt Orientation:
This is my favorite, one of the four bolts that hold down the assembly is different than the others. One of them is necked down to allow the oil from the head to get up into the rocker shaft. This bolt is also about 3/8 in longer than the others. Along with my shafts being installed upside down none of my bolts were necked down. The longer bolt goes in the second hole from the front on the left side and in the second hole from the back on the right side. Note that the High-Rise heads do not use a necked down bolt. On these heads have the oil passage in the rocker stand.
Well that about wraps it up, Oil holes down, Shaft support clamping splits out, and necked bolt in the right hole. Now just torque it all to 40-45 ft-lbs. Oh yea, don't forget the splash tray for the rocker assembly. Forgetting this will change the pushrod length slightly.