Thank you, Ted. That was an interesting read. Never thought about balancing the cam, but it makes sense. This also points out why I should subscribe to Y-Block Magazine. -Dave.

The fuel pump counterweight was used on the 1954, 1955 and the early 1956 Y engines.  When the fuel pump counterweight was eliminated during the ’56 model year, it was simply replaced with a washer of the same thickness.  At the same time the fuel pump counterweight was eliminated, the oil drip trough for the timing chain was also eliminated.  Here’s the exploded view showing both the counterweight and the spacer that replaced it.
  
It is interesting though how that fuel pump counterweight affected the balance aspects of the camshaft though.  Here’s the link to the article that was published in the Y-Block Magazine going into some of the nuances of balance with the counterweight versus no counterweight.
http://www.eatonbalancing.com/blog/2012/12/01/camshaft-balancing/ 

Lorena, Texas (South of Waco)

Problem found. The old cam was sent to be reground with the first spacer and key left in place. The regrinder couldn't use the old cam so sent him another and didn't see or forgot to return the spacer and key with it. 

57 Black Tbird 312/auto

Thanks Charlie, I can't remember what my Tbird has. Been too long since I built it and have done two FE's since so my memory is "cloudy".

57 Black Tbird 312/auto

I'm not sure about the year of the change, but there will be either the counterweight or a round spacer. Off memory, from the engine block forward, it should be thrust plate spacer (not keyed, woodruff key must be removed to install), timing gear, keyed spacer OR counterweight, eccentric, thick spacer, thick flat washer, bolt.



Lawrenceville, GA

Can someone explain the fuel pump counterweight applications for Yblocks? There is a guy on the FE forum that is rebuilding his 57 Ford 312 and is confused about whether it should have the counter weight or not. I have seen some reference to "early" yblock counterweights. Does this include 1957? Once again the Ford shop manual is confusing. It doesn't show a counterweight in the parts blow up of the cam shaft assembly but mentions it the text. It also has a photo of the assembled timing gear/chain with an arrow labeled "fuel pump counterweight" pointed to the area where it should be but it isn't there. The problem is the cam stub is sticking out too far for the bolt, washer and spacer to secure the upper timing gear. I think he may have misplaced the counterweight. Thanks.

57 Black Tbird 312/auto