good day ,
We are working on a beautiful 55 Mercury Montclair , that did have the Holley 4000 TEAPOT carb from the factory . 
That was replaced along with the 55 distributor in 1972 by a previous owner .
Holley 4160 with spacer on intake since 1972 and the front primaries do not open more than a third of the way .
of course vacuum secondary never opens . Previous owner did not drive this car very much , and I guess it ran good enough for him at the time .
The new owner and myself are looking to figure out why the oem linkage will not do the job of opening the primaries .
Was there a trick to this linkage ?? Special adjustments anywhere ???
It seems this was a very popular swap on the Y block back in the day .
thanks for the assist on this topic .

Is it possible that the four holes in the carb spacer/adapter or on the manifold's carburetor base/plenum are smaller in diameter than the 4160 carburetor butterflies? If so, they're keeping the butterflies from fully opening. What's the cfm of your 4160? Did you retain the original small-base intake manifold that was used with the Teapot?

Pull the carb and the adapter - then blot the two together.  Check to see if the butterflies open all the way or hit the adapter..  As blacktie said - that may be your problem.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

With the throttle linkage removed from the side of the carburetor, work the arm on the carburetor and observe if full throttle can now be obtained.  Also check the secondary throttle blades while doing this.  If no full throttle on either the primary or secondary sides of the carburetor, then the carb spacer/adapter is likely the issue.  If full throttle is available with the linkage removed, then obviously a linkage issue.  Could be a simple matter of adjustment or fabricating a longer link from the bell crank to the carburetor.  Keep in mind that the linkage for a ‘55/56 Teapot carbs is different than the linkage for the 57 & up carbs so that might be the root of the problem.  A lower pivot point for the linkage at the side of the carburetor might help depending upon which 4160 carb you have.

A picture showing what you have could possibly help.

Lorena, Texas (South of Waco)

All good ideas .and I thank everyone for the input .


Linkage off and Holley opens all the way with no issue , and Secondary linkage does not bind up at all at WOT .

What we are seeing is a linkage acting like nothing we have ever encountered in 50 years of carburetor work .

But I am not a Ford or Mercury expert , that is for sure .

Am going back to the Mercury tomorrow , it may be simple to fix or adjust , no experience on this set up ever .

ted , I believe you are correct about a linkage modification here .The actual rod that hooks to the Holly has a hole drilled special in order to locate the rod closer to the throttle blade pivot point .

will try to get some photos of this . The rod to the carb does not move well horizontally , and seems to want to drop down behind the casting of the intake manifold , .

If we ever get this part of it corrected this Y block sounds like she will be a real good driver .Thanks for all the help on this .
Joe Lamb 

UPDATE on 1955 292 with Holley 0-8007 carb , only opening the throttle 1/3 of the way .
we did finally remove all of the factory linkage and , cleaned and polished and painted all of it , new springs from Ace hardware .
improved opening by 30 degrees , so it was a big improvement .
Then we drilled a 3/16 new hole in the side of the Holley for the linkage rod to locate into , moving the hole location .3/8 of an inch closer to the pivot point of the throttle plate .
and finally took the original Ford carb linkage rod , we bent it at the carb end and this gave the carb the final geometry it needed to get the carb to open all the way .
Thanks to everyone that gave us help on this great Y block car .

Joe in Tampa