Early Gen 2 Camaro Engine Facts

by Alan Colvin on January 31, 2011

1970-75 CAMARO ENGINE CASTING IDENTIFICATION

The 1970-75 Camaros used a variety of blocks, cylinder heads, intake manifolds, exhaust manifolds, and waterpumps. In this article we will cover the identification of all these major engine components for all Camaro engines from 1970 through 1975. Both the information pertaining to each engine component and all pertinent information relating to each specific engine option are listed below the model year headings.

There were two plants that were casting cast iron parts for Chevrolet engines during this time period.  These were the Flint, Michigan, and Tonawanda, New York, plants.  All cylinder blocks, cylinder heads and cast iron intake manifolds cast in Saginaw, Michigan, for the Flint, Michigan, engine assembly plant would have a single-digit year date code.  Engines assembled in Flint with the single digit year code were used in both passenger and Corvette applications.  The Tonawanda engine plant cast their own castings at the engine plant.  All Tonawanda engine component castings will have a “T” cast into the surface of the part to designate it as a Tonawanda casting.

Always remember that when looking for specific dates you need to keep the following in mind.  First of all, try to verify the build date of your car. After the build date of your car has been verified, the actual dates you are looking for will be dated one to three months prior to the build date of the car.  This time elapse allowed for the assembly of that engine, transport to the car assembly plant and installation of that engine in your car.  There is documented proof that these engine plants would increase production leading up to possible strike periods, making it highly probable that many cars were built with engines way ahead (6 to 9 months) of thir respective build date. Another thing to consider if you have an original, untouched car, is to match the casting dates of the original parts still remaining on your car.  This procedure can prove to be dangerous unless you can verify that these dates still coincide with the build date.

This 2nd Generation Camaro casting number breakdown list is the first to ever be published anywhere. These casting numbers were compiled from the original Flint Engine Plant build records and extensive Tonawanda records as well. What we hope to accomplish with this article is to familiarize you with how and where to look for casting numbers on the 1970-75 Camaros.

Block Casting Number Identification

The block casting number is the single most important number on a block because it will probably be the last number on a block to be altered or changed to counterfeit or misrepresent a block.  The casting number is usually found at the rear left side of the block, on top of the bellhousing flange.  The casting date codes are cast in an alphanumeric sequence.  You should look closely at a block’s casting date because many blocks have been found that have been altered to represent an earlier or more expensive block.  The first digit will usually be a letter code, which specifies the month the block was cast.  Some casting dates have been found with all three digits represented as numbers, such as “345″, which decodes as March 4, 1965.  These types of dates are not common in restoration circles.  The month code letter designations are as follows:

A – January

B – February

C – March

D – April

E – May

F – June

G – July

H – August

I – September

J – October

K – November

L – December

The remaining digits in the date refer to the day of the month and year of the block casting.

Cylinder Head Casting Numbers

The cylinder head casting number is the single most important identifying feature on a head because, just like the block casting number, it will probably be the last characteristic to be altered or changed.  The casting number is usually found in between two valves and the rocker arm studs underneath the valve cover.  The casting date is usually found adjacent to the casting number. The casting date codes on small block cylinder heads can usually be found directly underneath the casting number.  You should look closely at a cylinder head’s casting date because many heads have been found that have been altered to represent an earlier or more expensive cylinder head.   The first digit in the casting date code will usually be a letter code, which specifies the month the head was cast. The month code letter designations are as follows:

A – January

B – February

C – March

D – April

E – May

F – June

G – July

H – August

I – September

J – October

K – November

L – December

The remaining digits in the date refer to the day of the month and calendar year of the head casting.

NOTE:  It should be noted here that some engines will use the same casting number, but have a different valve size.  Due to space limitations, the differentiating features of each cylinder head could not be included in this article.  This information will be included in a forthcoming article.

NOTE: The external identification symbols that are cast into the ends of each small block cylinder head could not be included in this article due to space limitations, but will be listed in a future article.


Intake Manifold Identification

All intake manifolds have a casting number which is found on top of the intake near the carburetor.  This number is raised above the actual casting of the manifold and is relatively easy to find.  Some intake manifolds have dates cast into the underside of the intake, some do not.  Most intakes have complete dates and some have dates written in an alpha code i.e. Jan=A, Feb=B, March=C, etc.; then the day and year will follow the month alpha code.  This dating system was sporadic at best.  Always use the casting number to identify.

Exhaust Manifold Identification

All Chevrolet factory exhaust manifolds are cast iron.  Since the manifolds are cast, the actual casting number and date are raised above the actual surface of the part. Most casting numbers are visible when the manifold is installed on the engine.  The casting number location and casting date location will vary from year to year and sometimes manifold to manifold.  Some manifolds will not carry a casting date at all.  Casting date codes follow the same pattern as engine blocks, but some do not carry a year.  The following is a breakdown of the casting date month codes:

Casting Date Month Code Identification

A – January

B – February

C – March

D – April

E – May

F – June

G – July

H – August

I – September

J – October

K – November

L – December

The number or numbers following the month code letter represent the day of the month that the manifold was cast.  Sometimes, but not always present, the last number indicates the year.

Waterpump Identification

It has been established from all known data available at this time that the dating of waterpumps is as follows:

WATERPUMP # DATE INFO

SMALL #3953692                                                                ALL DATED

BLOCK #6263701                                                                 ALL DATED

BIG BLOCK #3931065                                                         ALL DATED

#3969811                                                                                 ALL DATED

#6263707                                                                               ALL DATED

Casting date codes follow the same pattern as engine blocks, but some do not carry the year.  The month code is always a letter, followed by a number which signifies the day.  The last number signifies the year of production.

Example: B189

B: February

18: 18th day

9: 1969 (Refer to casting number to confirm)

Example: B1872 (Big Block Waterpumps Only Starting In 1970)

B: February

18: 18th Day

72: 1972

Casting Date Month Code Identification

A – January

B – February

C – March

D - April

E – May

F – June

G – July

H - August

I - September

J – October

K – November

L – December

1970-75 Camaro Casting Number Chart

1970 Camaro

307/200HP

Block Casting #3970020 (2 Bolt)

Head Casting #3927185

Intake Casting #3927183 (Cast Iron)

Exhaust Manifold Casting #

RH – 3932376 w/o AIR

LH   3942529 w/o AIR

Waterpump Casting #3953692


350/250HP

Block Casting #3970010 (2 Bolt)

Head Casting #3932441

Intake Casting #3916313 (Cast Iron)

Exhaust Manifold Casting #

RH – 3932376 w/o AIR

LH   3942529 w/o AIR

Waterpump Casting #3953692


350/300HP

Block Casting #3970010 (4 Bolt)

Head Casting #3947041

Intake Casting #3965577 (Cast Iron)

Exhaust Manifold Casting #

RH – 3932376 w/o AIR

LH   3942529 w/o AIR

Waterpump Casting #3953692


350/360HP

Block Casting #3970010 (4 Bolt)

Head Casting #3973414

Intake Casting #3927110 (Aluminum)

Exhaust Manifold Casting #

RH – 3946826 w/AIR

LH – 3942527 w/AIR

Waterpump Casting #3953692


402/350HP

Block Casting #3969854 (2 Bolt)

Head Casting #3964290

Intake Casting #3955287 (Cast Iron)

Exhaust Manifold Casting #

RH – 3909879

LH – 3916178

Waterpump Casting #3931065 (Early)  #3969811 (Late)


402/375HP

Block Casting #3969854 (4 Bolt)

Head Casting #3964291

Intake Casting #3963569 (Aluminum)

Exhaust Manifold Casting #

RH – 3909879

LH – 3916178

Waterpump Casting #3931065 (Early)  #3969811 (Late)


1971 Camaro

307/200HP

Block Casting #3970020 (2 Bolt)

Head Casting #3986339

Intake Casting #3973465 (Cast Iron)

Exhaust Manifold Casting #

RH – 3973432 w/o AIR

LH – 3989043 w/o AIR

Waterpump Casting #3953692


350/245HP

Block Casting #3970010 (2 Bolt)

Head Casting #3973487

Intake Casting #3973467 (Cast Iron)

Exhaust Manifold Casting #

RH – 3973432 w/o AIR

LH – 3989043 w/o AIR

Waterpump Casting #3953692


350/270HP

Block Casting #3970010 (2 Bolt)

Head Casting #3973487

Intake Casting #3973469 (Cast Iron)

Exhaust Manifold Casting #

RH – 3973432 w/o AIR

LH – 3989043 w/o AIR

Waterpump Casting #3953692


350/330HP

Block Casting #3970010 (4 Bolt)

Head Casting #3973487 or #3986316

Intake Casting #3959594

Exhaust Manifold Casting #

RH – 3986330 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #3953692


402/300HP

Block Casting #3969854 (2 Bolt)

Head Casting #3993820

Intake Casting #3955287

Exhaust Manifold Casting #

RH – 3989310

LH – 3989343

Waterpump Casting #3969811


1972 Camaro

307/130HP

Block Casting #3970020 (2 Bolt)

Head Casting #3998991

Intake Casting #6262936

Exhaust Manifold Casting #

RH – 3959562 w/NB2

3973432 w/o NB2

LH – 3989041 w/NB2

3989043 w/o NB2

Waterpump Casting #6263701


350/165HP

Block Casting #3970010 (2 Bolt)

*           Head Casting #3973487 (Early)

#3973487X/#3998993 (Late)

Intake Casting #6263752 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/NB2

3973432 w/o NB2

LH – 3989041 w/NB2

3989043 w/o NB2

Waterpump Casting #6263701


350/175HP

Block Casting #3970010 (2 Bolt)

*           Head Casting #3973487 (Early)

#3973487X/#3998993 (Late)

Intake Casting #6263751 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/NB2

3973432 w/o NB2

LH – 3989041 w/NB2

3989043 w/o NB2

Waterpump Casting #6263701


350/255HP

Block Casting #3970010 (4 Bolt)

Head Casting #3998916 (Unverified)

Intake Casting #3959594 (Aluminum)

Exhaust Manifold Casting #

RH – 3986330 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


402/240HP

Block Casting #3969854 (2 Bolt)

Head Casting #3999241

Intake Casting #6263753 (Cast Iron)

Exhaust Manifold Casting #

RH – 3989310

LH – 3989343

Waterpump Casting #6263707

* NOTE: IT IS UNCLEAR WHY THERE SEEMS TO BE AN USAGE OVERLAP FOR THESE TWO CYLINDER HEADS. UNTIL MORE PRECISE DATA SURFACES, BOTH HEADS ARE TO BE CONSIDERED CORRECT FOR BOTH APPLICATIONS.

1973 Camaro

307/115HP

Block Casting #3970020 (2 Bolt)

Head Casting #3998993

Intake Casting #6771061 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


350/145HP

Block Casting #3970010 (2 Bolt)

Head Casting #3998993

Intake Casting #3997773 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


350/175HP

Block Casting #3970010 (2 Bolt)

Head Casting #3998993

Intake Casting #3997771 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


350/245HP

Block Casting #3970010 (4 Bolt)

Head Casting #330545

Intake Casting #3997771 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


1974 Camaro

350/145HP

Block Casting #3970010 (2 Bolt)

Head Casting #333882

Intake Casting #340266 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


350/160HP

Block Casting #3970010 (2 Bolt)

Head Casting #333882

Intake Casting #340261 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


350/185HP

Block Casting #3970010 (2 Bolt)

Head Casting #333882

Intake Casting #340261 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


350/245HP

Block Casting #3970010 (4 Bolt)

Head Casting #333881

Intake Casting #340261 (Cast Iron)

Exhaust Manifold Casting #

RH – 3959562 w/AIR

LH – 3989041 w/AIR

Waterpump Casting #6263701


1975 Camaro

350/145HP

Block Casting #3970010 (2 Bolt)

Head Casting #333882

Intake Casting #346260 (Cast Iron)

Exhaust Manifold Casting #

RH – 346248

LH – 346247

Waterpump Casting #6263701


350/155HP

Block Casting #3970010 (2 Bolt)

Head Casting #333882

Intake Casting #346249 (Cast Iron)

Exhaust Manifold Casting #

RH – 346248

LH – 346247

Waterpump Casting #6263701

Note: This information can also be found in the 1970-75 Chevrolet by the Numbers book available in my store on this website.

{ 1 comment… read it below or add one }

DUANE WILSON February 23, 2011 at 3:17 pm

THIS IS GOOD INFORMATION TO HAVE
AND LOOKING FOWARD FOR MORE INFORMATION LIKE THIS

THANKS
DUANE

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