My Service Manual shows in Figure 54 on page 182 (photo attached) that you should use a flat washer and a lock washer with the screw to hold down the Rocker Assembly brackets on the two ends and also the bracket in the middle. And you don't use a lock washer on the two bracket studs, just a flat washer. I attached my Rocker Assemblies like this and ran to oil pump with a drill and watched how the Rocker Assemblies oiled. From the center bracket, a stream of oil about the size of 3/16 drill bit poured out. This is because of the split in the lock washer. I removed the lock washer from the center bracket and just installed a flat washer to try to seal off this oil leak. When I ran the oil pump again, no oil cam out of the bracket and all oil went through the holes in the arm to the rockers.
It seems to me like this much oil leaking out of the center bracket would reduce oil pressure inside of the shaft and cause greatly reduced oil flow to the rockers. Especially since oil is only sent to the Rocker Assembly one time per revolution of the cam. So I left the lock washer off of the center bracket and just installed a flat washer. Lock washers on the two ends are not a problem because these two brackets are outside of the pressure envelope in the shaft. I considered if this oil leaking out of the center bracket would splash around and help oil the rockers and it would not. It just pours straight down to the top of the head and back to the oil drain holes to the oil pan.
I don't know how the Rocker Assemblies were originally attached at the factory. But just wanted to share this so you could consider this if you are working on your heads.
Posted 2020-05-15 4:29 AM (#598305 - in reply to #598281) Subject: Re: 1955 V8 Poly Head Rocker Assembly Installation
Location: Beaumont TX
Your diagrams sure show up good. On bbdakota's engine, which has a beautiful paint job by the way, he did not install any lock washers on the 3 bolts holding down the rocker arm assembly. The three bolts, not the two studs where the oil comes up, are supposed to have lock washers according to Figure 58. Should be bolt head, lock washer, and flat washer and the flat washer goes against the bracket. In figure 58 above, it says bracket, screw, washer and lock washer on all three bolts and the last one is the locating bolt which also has a lock washer. The lock washer on the drawing on Figure 58 doesn't show but if you look in the parts catalogue, Page 9 - 14, at the rocker assembly, it shows that a split type lock washer, 9-43-26, goes between the head of the bolt and the flat washer.
BBdakota's install is good on the center bolt I believe, even though it is not like Figure 58 says to do it. I think it is better to leave the lock washer out because you don't lose oil pressure going to the rockers. In other words, I think BBdakota is right and Figure 58 is wrong for the bolt in the center of the rocker arm assembly. He could have put the lock washer between the bolt head and the flat washer on the two bolts on either end and that would have been according to Figure 58. This is not a problem because the two end bolts are not inside the oil pressure part of the shaft. Furthermore, I think it is fine just to leave the lock washers out like he did. I put the lock washers in on mine. But the reason I posted this is because of what the service manual says to do. And I think putting a lock washer on the center bolt is not a good thing to do because you lose oil pressure inside the rocker shaft.