Understanding the "load-a'matic" distributor

[BUBBAS IGNITION]

UNDERSTANDING THE LOAD-A-MATIC FULL VACUUM DISTRIBUTORS
JIM LINDER “BUBBAS Hot Rod Shop” www.bubbashotrodshop.com

Ford made the “load-a’matic (full vacuum) distributor from 1949 until 1957 on most of their engines . This distributor is very much mis-understood by many owners etc.
The load a matic works by adding spark advance thru a vacuum chamber using vacuum differential at the carburetor.This vacuum signal from the carb is very low with advance typically starting at ½ inch of vacuum and being full advance at 2 inchs of vacuum.
The slightest change in the engine vacuum makes this unit become a problem and not supply the correct signal. A carb change is the most common problem making this unit not work. Twin carbs, a camshaft change also makes the unit become inoperative. I have talked to many owners with the vacuum line disconnected with complaints of engine overheating ( retarded ignition timing) and a poor running engine.

The “fix” for this problem is to use a later distributor that has full centrifugal advance that needs no vacuum signal and is operated by rpm alone . ( may also use vacuum advance as well on some units)

For the 1949-53 Flatheads we offer a remachined Chevrolet unit with a curved mechanical advace suitable for the flathead engine design. We have built and shipped over 700 of these units to very happy customers over the last years..
$180 plus $18 shipping

The 223 six is another story and requires some more thought as the oil pump drive is different at the base of the distributor . Ford offers at least three different drives with a spade, 5/16 hex and a 3/8 hex drive for the distributor oil pump drive.
For these we use a “ butt change” we take the lower drive end of your existing unit and mate it to a later ( full mechanical advance) unit, use another distributor ( like a Chevrolet six) or a older Mallory etc.
$250 plus $18 shipping


Picture on left is early “full vacuum” load a matic design, note exposed springs and adjustable pins. Picture on the right is the later centrifugal advance with weights and springs under the point plate.