Thank you for allowing me to join the forums! Google searches just keep spinning me around in circles.
Essentially, just looking to be properly educated as to what I own, and what else has been done incorrectly.
1955 Thunderbird, 292, 6V Pos Grnd, Fordomatic, 43K original miles.  

I'm the 3rd owner as of 3 months ago, and have been uncovering some 'unique' issues that were apparently performed by the previous owner's 'mechanic'.
My bird has a Mallory YC dual-point distributor, with (I'm guessing) a tach drive cable. 
I've already discovered that the rotor was incorrect (too large) so the contacts under the cap were filed down to compensate (!!!) She ran fine, until she got too warm, and then re-starting was a chore.
My question(s):
> Were the YC's ever installed at the factory or only as replacements (upgrades?) later on?
> My understanding is the 55's Tach was vacuum driven off the distributor, but there's only a cable going to my tach and no vacuum lines coming from the distributor.  
> Is it wise for me to tackle swapping it out to the stock-type 55 Tbird distributor, so I can convert to electronic ignition (Pertronix doesn't make a kit for the YC's)
Thanks in advance!  

Welcome to the site.

The Thunderbird and other cars (seldom) use a straight mechanical drive to the tach. The only other thing at the tach is the dash light bulb. I’m guessing your Mallory has no vacuum advance.

The original 55 tach was a Loadomatic design. It had no centrifugal weights, all advance was handled by the vacuum connection from the carburetor to the tach. That was a matched pair, can’t change one without changing the other (or modifying the carb, we’re ignore that for now).

Your tach should work with the Mallory, and I’m guessing it would have had the correct drive gear in the distributor to be a hook up and go. So if it’s not working, that’s a separate issue.

If you want to restore it to stock, you’ll need to make sure you’ve got the right carburetor, others here know more about that than I do. But aside from a gas mileage issue, you shouldn’t need anything but a properly working Mallory and a properly set up carburetor to drive just fine.

Try posting a couple pictures with the air cleaner off, that will tell a lot. And don’t give that distributor away, those are highly sought after by the hot rod crowd. With a dual point Mallory, especially in a bird where access is good, I wouldn’t change to any electronics ignition if you can get the new Mallory parts. Does it have the big external condenser? Those are getting pretty rare I’m told.

Enjoy the ride, sounds like a great one.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Mallory distributors were aftermarket items, not installed at the factory.  The tachometers in the Birds were cable driven from the distributor.  Bird distributors had a unique casting which included the tach cable attachment point.  Passenger car distributors did not have a cable attachment point.  The '55 distributors were advanced by vacuum only, which is probably why the Mallory has been installed to take advantage of mechanical advance.  The carburetor and distributor are a "matched pair".  Your carburetor may have been changed to a later style, so the original distributor would not work properly with a different carb.  You would not be happy with the '55 distributor if the carb is not a "5 carb. 

John - "The Hoosier Hurricane"

Miker posted his reply very shortly before I posted mine, but our replies say the same thing.  Sorry Miker..  

John - "The Hoosier Hurricane"

Thanks for the replies, and helping to fill in more puzzle pieces.
I've attached some pics (I hope) to help with my feeble descriptions...   (Note the plugged vacuum line on the carb)

You do have a '55 "teapot" carb, so a '55 distributor will work as well as it originally did if all systems are operational as the factory produced it.     You probably would like it better as it is now, however.  The plugged vacuum line would be connected to the vacuum diaphragm on the distributor. 

John - "The Hoosier Hurricane"

The YC is a centrifugal distributor only. The stock 55 carb work with a vacuum only distributor but since your distributor has been changed and the vacuum port plugged everything will work. As long as the rotor doesn’t touch the contacts and it didn’t crack the cap it really doesn’t know or care as long as it fits snugly on the main shaft. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I have a Mallory Y-Block distributor with a vacuum port. Only one I've ever seen.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Peteronix does make a kit for the Mallory, ML 181 & 9 ML181, & 7 ML 181 for Ignitor 1,2,& 3.  Look in the back in the catalogue.  One thing, the points are becoming harder to find, and the large condensers are not being reproduced. NAPA did sell standard looking distributor cap and rotor (echlin) i think) that fit the Malory Distributor                                                                                                                                                                                                                                         
. EDIT  (distributor cap # ECH-FA78 )

Gary Ryan San Antonio.TX.

I run a Mallory also, along with a Mallory coil and resistor.  In setting mine up I have found pulling the distributor to set the points is best.  While it is out, good idea to clean the caps contacts, both the rotor side and spark plug wire spikes.  I’ve seen points, rotors,  on eBay.