Chevelle/Corvette LS6 Registry LS6 Engine Codes / Casting Dates

Engine			Transmission	Notes
1970 Chevelle (1)
Code	Size-Carb	HP-RPO
CRR	454-4	450-LS6	TH-400
CRS(1)	454-4	450-LS6 (w/L89)	TH-400	Aluminum Heads
CRV	454-4	450-LS6	Manual M22
CRX	454-4	450-LS6	Manual M22	Heavy Duty Clutch
CRY(1)	454-4	450-LS6 (w/L89)	Manual M22	Aluminum Heads/Heavy Duty Clutch
1971 Corvette (2)
CPW	454-4	450-LS6	Manual M22	Aluminum Heads
CPX	454-4	450-LS6	TH-400	Aluminum Heads

⁽¹⁾ There is some discussion about the 1970 Chevelle LS6-454 being sold with aluminum heads. One very respected source says that according to records at Tonawanda, no 454 engines came with aluminum heads. Their records indicate the L89 option was cancelled (not replaced) with the demise of the L78/L89 396 (402) engine combination. On the other hand, some have reported seeing the CRS code on engine blocks and one registrant here has a dealer bill-of-sale plus the warranty protect-o-plate card both showing the CRY code. A total of 4,475 RPO LS6 options sold with 1970 Chevelles with the Mlaibu series sport coupe, convertible, and El Camino. There is no 'official' breakdown of how mny of any body style were sold.

⁽²⁾ There were only 188 RPO LS6 options sold in 1971 and all were Corvettes and sold with aluminum heads.

1970 Chevelle

Engine Specifications:
454 cubic inches
450 horsepower @ 5600 RPM
500 pound-feet torque @ 3600 RPM

Block ~ Casting number 3963512
* Bore ~ 4.21"
* Stroke ~ 4.00"

Heads ~ Casting number 3964291 - 1970 Cast Iron
* Closed chamber square port cast iron
* Intake valve size ~ 2.19"
* Exhaust valve size ~ 1.88"
* Combustion chamber ~ 109.037cc
* Castings used both "N" and "peanut" plugs
* Compression ratio ~ 11.25:1

Carburetor ~ Holley
** Manual Transmission
* List 4491, 454 (CA-w/E.E.C.), M/T, #3967479 GM
* List 4557, 454 (FED-w/o E.E.C.), M/T, #3967477 GG
** Automatic Transmission
* List 4556, 454 (CA)-w/E.E.C., A/T, 3969894 GP
* List 4492, 454 (FED-w/o E.E.C.), A/T, #3969898 GR

Intake Manifold ~ Casting number 3963569
* Aluminum low-rise. Carburetor is 1.25" above cylinder head ports.

Exhaust Manifolds ~ Used on other Chevrolet models and other years
* RH ~ Casting number 3916178
* LH ~ Casting number 3909879

Distributor
* Stamped number 1111437

Camshaft
* Same camshaft used with 402/375hp engine
* Casting number 3904366
* Part number 3904362
* Mechanical lifter
* Intake & Exhaust lift .520"
* Intake duration 316 degrees
* Exhaust duration 302 degrees

Crankshaft ~ Casting number 3521
* Forged steel
* Stroke 4.00"

LS6 Piston Specs
* Domed head used only in this application.
* Weight 29.12 ounces
* Impact extruded alloy aluminum. 

1971 Corvette

Engine Specifications:
454 cubic inches
425 horsepower @ 5600 RPM
475 pound-feet torque @ 3600 RPM

Heads ~ Casting number 3946074 - Aluminum 1971
* Closed chamber square port cast iron
* Intake valve size ~ 2.19"
* Exhaust valve size ~ 1.88"
* Combustion chamber ~ 118.000cc
* Compression ratio ~ 11.25:1

Carburetor ~ Holley
** Manual Transmission
* M/T, 3986195
** Automatic Transmission
* A/T, 3986196

Intake Manifold ~ Casting number 3963569
* Aluminum low-rise. Carburetor is 1.25" above cylinder head ports.

Exhaust Manifolds
* RH ~ Casting number - xxxxxxx
* LH ~ Casting number 3880869

Distributor
* Automatic transmission -1102063
* Manual transmission -1102076

Camshaft
* Casting number 3904366
* Part number 3904362
* Mechanical lifter
* Intake & Exhaust lift .520"
* Intake duration 316 degrees
* Exhaust duration 302 degrees

Crankshaft ~ Casting number 3521
* Forged steel
* Stroke 4.00"
Casting Dates
* The following is applicable to cylinder heads, engine blocks, intake manifolds, exhaust manifolds, and water pumps.

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 following is applicable to alternators, distributors, and starter motors. Note electrical items did NOT use the letter "I" because it could be easily confused with the number "1."

A - January	B - February	C - March	D - April
E - May	F - June	G - July	H - August
J - September	K - October	L - November	M - December

Holley Carburetor Dates

Holley Three-Digit Date Codes - Through 1972
1st Digit		2nd Digit		3rd Digit
Stamp	Year	Stamp	Month	Stamp	Week
5	1965	1	January	1	1st week
6	1966	2	February	2	2nd week
7	1967	3	March	3	3rd week
8	1968	4	April	4	4th week
9	1969	5	May	5	5th week
0	1970	6	June
1	1971	7	July
2	1972	8	August
		9	September
		0	October
		A	November
		B	December

 

Home | Arlington | Atlanta | Baltimore | Flint | Kansas City | Van Nuys | Canada | Gallery | Tech/Tools | FAQ | Contact Me | Register | Chevelle Gifts | Orphaned LS6 Equipment

Privacy Policy

The LS6 Showcase & Registry respects your privacy. The LS6 Showcase & Registry will not give your personal information, i.e., name, address, email address, et al. or complete VIN sequence to any third party and does not sell any registrant's data to anyone. If anyone inquires about a particular car in the registry, the admin will forward that information request to the registered car's owner and let that owner decide how to respond to the inquiry.

If you have any further questions, feel free to contact the site administrator via the contact page.

This website is designed and maintained by Webs by Dale™ (WBD). This website was created as a showplace for LS6-optioned Chevelles/Corvettes. WBD shall not be held liable for any loss resulting from the use of the information contained on this website. This website is the sole property of WBD. Design, layout and website photographic images were all created by WBD or submitted by readers and are not to be copied or distributed without express consent from WBD in writing. Use of WBD name, logo and identity is strictly prohibited by law.

All submitted photos become the property of WBD and may be used for any legitimate purpose on this and other websites in the Webs By Dale family or any print publications (books/calendars/CDs/et al.) associated with this author's efforts without payment expected or due to the contributor. Submitted photos by any registrant may be used by WBD for display on any other WBD website without compensation.

While every effort is made to ensure the Chevrolets on this website are what they claim to be, WBD does not verify the cars beyond what documentation is provided. One must take their due diligence in seeking to purchase any Chevrolet and not rely on any website, including this one, to validate the bona fides of any owner's claim.

This registry and showcase website is not designed to help you locate a car you owned 20-30 years ago. To my knowledge there is no known database of a car's VIN and its past/current owner. Such a public database would be a gross invasion of privacy. The  LS6-optioned Chevelles/Corvettes listed here are done so by the current owner at time of registration and may have changed hands since registration. If you are seeking information on any vehicle registered here, this website will only contact the owner with your request and it will be up to them if they contact you or not.

Active since September 2008 - Today is