Steve : I replaced my '54 Merc teapot with a Holley 390, and installed a modified '57 distributor (using the '54 gear and oil pump drive). I had to use an adaptor on the original intake to avoid port mismatch. The adaptor was the tapered type which provides a smooth transition from the Holley base to the original intake bores. Best thing I could have done as the engine came alive and I now get 23.5 MPG with absolutely no more carb or timing issues. Set the initial timing at 10 deg. Good luck : Bruce 

I would agree with Charlie on the size of carburetor. The 390 Holley or the WCFB I feel is a better match for the size of engine.  You'll have better throttle response and a much more efficient setup.  Carburetors and cam shafts seem to fall into the category that bigger is better!

Jeff Petersen

One guy's opinion, Steve...Hold out for a '54 Merc four barrel intake manifold.  You want this for port alignment with your '54 heads.
As mentioned, Speedway is a source for adapters for later four barrel carbs to the early '54, 55, and '56 4 bbl. intake manifolds.  Vintage Speed (Charlie Price) in Florida is another source for carb adapters.With the '54 Merc 256 engine displacement, IF you're going to go with a four barrel carburetor, consider looking at the Holley Carburetor web site.  Under the heading 'Products' you'll find a listing for 'Street Performance Carburetors'.  When you toggle that heading there is a sub heading 'Street Performance - Traditional'.  In the 'Street Performance - Traditional' listing you will find a Model 0-8007 390 cfm carburetor with electric choke and vacuum secondaries.  Holley offers numerous packages and components for installing this carb. when you toggle that carb listing.
IMO, with the small primary throttle plates and vacuum secondaries, this carb will give you the throttle response and drive-ability I THINK you want for street use.  My recollection is that the factory installed '55 and '56 FoMoCo Holley 4000s used on 292 and 312 engines had a rating of 330 cfm.

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Ports on '55-'56 manifolds are larger than '54, but not quite as large a '57.  They would come closer to sealing than '57s would.

John - "The Hoosier Hurricane"

Mark

1956 Mercury M100
1955 Ford Fairlane Club Sedan
Delta, British Columbia

I have located an intake manifold , it has casting numbers ECB 9426B on it. It appears from the top side  to be the same as the 54 Merc EBY 9426 D manifold. My question is the head ports size, will they match up to the original 54 Mercury heads???  This ECB 9426B was originally on a 55 Ford 272 or 292. I am thinking that the head ports were not increased in size till the 312 of 56 and 57. Does anybody know that for sure??? 

I am still looking for an original 54 Mercury intake, which would be the EBY 9426 D, But just now ran across this ECB 9426B on ebay , that's why I am posting this question.
Any leads on who might have a spare 54 Mercury intake to sell would be appreciated. 
Thanks.

If you replace the distributor and it has a 13 tooth gear and tang drive, you'll have to replace the gear, oil pump and tang drive to a hex drive. Your new distributor will have 14 teeth.

  Dennis in Lititz PA

If you replace your Holley 4000 "teapot" ... DO NOT USE YOUR OLD LOAD-O-MATIC distributor. Replace it with a 57-64 unit. You can still get them at places like CARQUEST, O-Reilly's, Autozone, Etc.Off the shelf, the Edelbrock is probably the easiest to install and run right out of the box.On the adapter, check Speedway. I have one myself for a test engine run stand, but I cannot remember the part number to the adapter.EDIT: Link is here... http://www.speedwaymotors.com/Universal-Carb-Adapter-Tapered-Port,69.html

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

I reckon the edelbrock 500 would work fine.you can use an adaptor to make it fit your manifold.I would certainly use the 57 and later distributor! Another thing you could do if you wanted is to find one of the old small base WCFB carbs from the same era and rebuild it.When I was a young guy that was generally the first thing we did on any teapot equipped Y block we had and those WCFB carbs worked well.

I have searched through past posts and there are lots of threads on this topic for 55/56 Fords , but found nothing on the 54 Mercury 256 y-block. I have made up my mind on replacing the tea pot and going to a later Holley/edelbrock or even autolite 4100 carb. My choice would be the smaller edelbrock, 500 cfm.