Pontiac Automotive Battery Boot Camp
Part I: The Tar-Top 1955-1966
Your Pontiac battery is one of the most crucial components of a concours-quality restoration. One to five points can be deducted from your score in the Concours Stock Restored Class at POCI depending upon the degree of deviation from factory original or a correct-appearing reproduction. The right battery is an eye-catcher, too. Its presence is an important detail that allows you to go back in time and experience the joy an original owner felt when he looked down at his Pontiac's engine compartment for the very first time.
Pontiac Motor Division began using 12-volt batteries-made exclusively by Delco-Remy in 1955-a full two years after they were first introduced into Cadillacs and Buicks. From 1955-1966, Pontiac introduced a series of six Delco-Remy batteries into its new vehicles.
Let's take a look at each so you can identify the correct battery for your '55-'66 Pontiac. Then we'll answer the most popular questions about classic Delco-Remy batteries and lead-acid batteries in general. Finally, we'll show you how to decipher the date-code on an original Delco-Remy battery, and how to determine the correct date-code for your reproduction battery. But that's not all.
Next month, come back for Part II where we'll explore the Delco-Remy Energizer hard-top batteries that powered Pontiacs from 1966-1975.
HPP thanks John Sawruk for his research and valuable assistance in making this article possible and Restoration Battery for providing its expertise and products for photographs.
Delco-Remy 2SMR53/458 Battery
In 1957, the Delco battery model number was changed to 2SMR53/458. This battery was used in '58, '59 and '60 Pontiacs. Solid yellow vent caps were used through December 1959. Beginning in January 1960, the yellow vent caps had the word "DELCO" painted black.
Physical Features 2SMR53/458 • GM Part No. 1980458 • 1958-1960
It appears very similar to the '56 2SMR53, except the upper edge was stamped "CAT. NO. 458" (instead of "2SMR53"), which was still not visible when installed in the car.
The upper flat area reads (in an indentation) "2SMR53/458."
The center area is stippled, except for a large smooth area that reads "DELCO ORIGINAL EQUIPMENT LINE."
Above the "flat" area (in the stippling) reads "RUBBER SEPARATORS - HARD RUBBER CASE."
Below the "flat" area (in the stippling) reads "A GENERAL MOTORS PRODUCT."
The left side also has a smooth indentation with the words "DELCO-REMY. ANDERSON, INDIANA. MADE IN USA."
Delco-Remy 2SM50 Battery
In 1955, Pontiac used Delco model 2SM50. It was the first Delco Group 24 12-volt battery that employed a hard rubber case, though it still used wooden separators to divide the lead plates. The separators were made from either cedar or Douglas fir, and lead straps over the partitions connected the cells (connectors). It was the last year for wooden separators and for the black Delco vent caps with the yellow ring.
Physical Features 2SM50 battery • GM Part No. 1890488 • 1955 only
2SM50 is stamped on the upper edge, but this model number isn't visible when the battery is installed in the car.
The GM Part No. doesn't appear anywhere on the battery.
The upper flat area reads (in an indentation) "50AMP-HR."
The center area reads "DELCO" in large letters on a stippled background.
One-third of the bottom area is flat and reads "DELCO-REMY. ANDERSON, INDIANA.MADE IN USA . GENUINE HARD RUBBER."
The left side also has a smooth indentation with the words "DELCO-REMY. ANDERSON,INDIANA. MADE IN USA."

Delco-Remy 2SMR53 Battery
For 1956, Delco-Remy introduced the 2SMR53. This 53-amp HR battery used both the hard rubber case and hard rubber separators. The latter were thinner than the wood separators, which allowed more active plate material and thus a higher battery capacity. Vent caps were changed to a solid yellow with "DELCO" in large letters.
Physical Features 2SMR53 • GM Part No. 1890587
1956-1957
The model number was again stamped on the upper lip, but also isn't visible when the battery is installed in the car.
The upper flat area reads (in an indentation) "2SMR53."
The center area is stippled, except fora large smooth area that reads "DELCO ORIGINAL EQUIPMENT LINE."
Above the "flat" area (in the stippling) reads "RUBBER SEPARATORS - HARD RUBBER CASE."
Below the "flat" area (in the stippling) reads "A GENERAL MOTORS PRODUCT."
The left side also has a smooth indentation with the words "DELCO-REMY. ANDERSON,INDIANA. MADE IN USA."

Delco-Remy 554 DC-12 Battery
The Delco battery installed in the '61 to '63 four-cylinder Pontiac Tempest (only) was a 554 DC-12. This was a smaller battery, known as a group 22F. Its dimensions were 9 inches long by 63/4 inches wide and 9 inches high to the top of the post. It had yellow vent caps with "DELCO" painted black.
Physical Features 554 DC-12 • GM Part No. 1980554 • 1961-1963
The center area is stippled except for a large smooth area that reads "RUBBER SEPARATORS HARD RUBBER CASE DELCO ORIGINAL EQUIPMENT LINE."

Delco-Remy 458 DC-12 Battery
In 1961, Delco-Remy changed its contract battery to the more familiar DC-12.
Physical Features458 DC-12 • GM Part No. 1980458 • 1961 only
The upper front area of the battery is flat. In the center of the flat area (inside an indentation) is the number 459, which is not visible when installed. This is true even though the battery is a 458. See Frequently Asked Questions for further explanation.
In the center of the stippled area in flat lettering reads "DELCO DC-12 ORIGINAL EQUIPMENT DRY CHARGE."
The lower front is a smooth area with a "large" and a "small" indentation.
Inside the large indentation reads "STARTING POWER RATINGS
(300 AMPS. AT 0 DEGREES F)
CRANKING MINUTES
1.6 ... VOLTAGE AT
10-SEC. 6.6." Inside the small indentation reads "AMPERE HOUR RATING 53."

How To Read Your Battery Date Code
All Delco-Remy tar-top batteries were date-coded with a production date and a battery plant designation.The following letters were used to designate battery plants in date coding:X = New Brunswick, New JerseyT = Muncie, IndianaS = Anaheim, CaliforniaV = Olathe, Kansas
The letters A through M are for month designations:
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
J = September
K = October
L = November
M = December
(The letter "I" was NOT used.)
Date coding example: 9CT
9 = Year: 1959
C = Month: March
T = Plant: Muncie, Indiana
When the hard-top batteries were produced, a specific day was also added to the date coding.
Date coding example: 7DV 12
7 = Year: 1967
D = Month: April
V = Plant: Olathe, Kansas
12 = 12th day of the month
Most Delco batteries were manufactured about 30 days before they were installed into Pontiacs at the assembly plants.
Delco-Remy 558 DC-12 Battery
In 1962, Pontiac started using the 558 DC-12, which was much more powerful than the 12V battery used in previous years. However, it still retained Group 24 size specifications. The case has both 558 and 559 stampings (see Frequently Asked Questions for explanation). The 558 DC-12 battery employed offset top covers to enable increased capacity without enlarging the case. Top covers are the areas that protrude out of the tar (on top of the battery, which the vent caps screw into). Prior to 1962, the batteries used centerline top covers.
This battery also used yellow vent caps with "DELCO" painted in black.
This same 558 DC-12 battery was used in Pontiacs through 1966, with the following minor changes. On July 16, 1962, General Motors chief designer Bill Mitchell requested that the yellow vent caps be replaced on all Delco contract batteries, stating that the yellow was distracting from the beauty of the engine. Thus, all Pontiacs assembled after December 31, 1962, had batteries with black vent caps and "DELCO" painted in yellow.
In 1966, Delco-Remy added a flange to the bottom of the 558 DC-12 battery, without retooling the case. The GM Part No. also changed to 1980506. This flange is actually an indentation in the bottom (front and back), to enable the use of the new bottom battery hold-down clamp. Though Pontiac did not use a bottom hold-down clamp in 1966, all Delco-Remy batteries were produced with the flange.
Physical Features
Delco 558 DC12 • GM Part No. 1980558 • 1962-1966 The upper edge of the case was stamped CAT. NO. 558. It was still not visible when installed.
The front of the 558 DC-12 appears very similar to the 458 DC-12 with several changes in the wording molded into the battery.
The upper front area of the battery is still flat. In the center of the flat area (inside an indentation) is the number 559.
In the center of the stippled area, (still in flat lettering) reads "DELCO DC-12 ORIGINAL EQUIPMENT LINE POWER RATED."
The lower front has a smooth area, with a large and a small indentation. Inside the large indentation reads "STARTING POWER RATINGS (300 AMPS. AT 0 DEGREES F) CRANKING MINUTES 1.6... VOLTAGE AT 10 SEC. 7.7."
Inside the small indentation reads "AMPERE HOUR RATING 61."

Frequently Asked Battery Questions
Q: What is a contract battery?
A: A contract battery was manufactured as a new part for Pontiacs. All batteries installed in vehicles at Pontiac assembly plants were considered "contract" batteries. Delco-Remy, even though it was a division of General Motors, was required to bid for the contracts to supply batteries to assembly plants. Thus, to keep its costs down, Delco-Remy never painted contract batteries.
Q: What is a counter battery?
A: A counter battery was manufactured for sale at Pontiac dealership service counters and at Delco-Remy retailers.
Q: Is there a difference in internal design between contract and counter batteries?
A: No.
Q: Do contract and counter batteries appear the same?
A: No. A contract battery was never letter-painted. A counter battery was letter-painted by Delco-Remy before being shipped to a dealer for retail sale.
Q: What is a tar-top battery?
A: The tar-top battery earned its name from the tar that was used to seal the six individual top covers. Tar-top batteries were used at Pontiac through 1966, in most applications.
Q: What is a lead-acid battery?
A: A lead-acid unit utilizes electrodes of lead metal and lead oxide in an electrolyte of sulfuric acid to store voltage. It's the design used by Delco-Remy in most of its Pontiac applications through 1975. Lead-acid batteries may sometimes spew acid out of the vent caps if they're overfilled or overcharged. This acid can corrode battery cables, battery hold-downs, battery boxes and discolor the paint on vent caps.
Q: What's inside a lead-acid battery?
A: Each 12-volt battery case is divided into six cells by walls called partitions. Each cell contains separators. (The number of separators varies by the amount of lead plates per cell.) Each of the separators has lead plates attached. The lead plates of each cell are joined to one another by "connectors." More lead plates per cell means more cranking power for the battery.
Q: Why are vent caps used in lead-acid batteries?
A: To let the pressure out of the case because gases will build up as the battery charges and discharges due to the electrolytes (acid). Vent caps can also be removed to check water levels and to check specific gravity with a hydrometer.
Q: What does a battery group number mean?
A: A battery group number is an industry-standard specification for batteries, defined and regulated by the Battery Council International (BCI), formerly called The Association of American Battery Manufacturers (AABM). The purpose of BCI is to set up guidelines the battery manufacturers adhere to. All '55 through '69 Pontiacs (excluding 4-cylinder '61-'63 Tempests) used a Group 24 battery, which measures 101/4 inches long by 63/4 inches wide and 9 inches high to the top of the post. All Group 24 batteries are top post. In 1970, Delco-Remy introduced the Group 74 side terminal battery at 101/4 inches long, 7 inches wide and 83/4 inches high (to the top cover). In the Pontiac line, it was first installed in cars equipped with the 455 engine.
Q: Why is my battery imprinted with "459" when the battery model number is really 458?
A: Delco-Remy used the same battery cases to make both the "wet" and "dry" batteries, and to save money. Your Pontiac shipped with a wet battery and Pontiac service parts dealers sold dry batteries. Example: 459 or 559 (odd numbers) signify the dry model on the front and 458 or 558 (even numbers) signify the wet model stamped into the top.
Q: What is the difference between a wet and dry battery?
A: A wet battery is delivered fully operational with electrolytes added. Conversely, a dry battery is purchased requiring four quarts of electrolytes and charging before it's ready for use. Water is then added as needed to maintain the correct electrolyte level.
Q: I found an NOS Delco-Remy battery online. Is it valuable?
A: Probably not, for three reasons. First, the NOS batteries remaining in the hobby are counter batteries and don't correctly match the black contract battery and date-code that shipped in your Pontiac when it left the factory. Secondly, NOS batteries decay over time and do not hold a charge properly. Third, NOS counter batteries have a warranty "punch-out" decal that was never applied to your original battery.
Q: Is a reproduction battery a better choice than an NOS battery?
A: Absolutely! Reproduction Delco-Remy batteries from the supplier we contacted are correct in appearance to the battery that was supplied in your new Pontiac. They also use current technology to maintain long life, and sufficient cranking amps to start your classic Pontiac without worry.
Conclusion
Next month, Delco-Remy enters the musclecar era with the famous Delco Energizer R59, the side-terminal R79/R89 and the torque-taming R89W. Plus, Pontiac's very first maintenance-free battery, a commentary from Pontiac historian John Sawruk on POCI judging of your battery, and more.

Photo Gallery: Pontiac Automotive Battery Boot Camp - High Performance Magazine



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