Has anybody ever heard of or seen an LS6 Chevelle with aluminum heads?Many books list this option and give the engine suffix code of CRS.Apparently these aluminum heads were only available with an automatic transmission.I seen such a car for sale in Tarpon Springs Florida at a classic chevy place.The car was a bench seat column shift car with no options.It was forest green.The buld sheet and protecto plate looked fake,but I am no expert.I also heard some people say they never made such a car and that car is a complete bogas car with made up documents.The car did sell to a man in Missisippi or Alabama for BIG $$$$$$.I always was curious to such a car.Does anyone know about this rarely talked about option?Some books list it others dont.I now about the rare L89 396/375 70 Chevelle that records say 18 were built but no such records on the CRS 454 /450 aluminum head motor.What a mystery!!

It sounds fishy. I've heard 18 as the figure of '70 L89s, but as for the LS6 with aluminum heads... Actually, in '71 I've heard that aluminum heads were available on the LS6 in the Corvettes. That's not to say Chevy couldn't have done it in '70 on LS6 Chevelles. I have heard that Chevy planned on releasing an LS6 or even LS7 in the Nova, or some tri-power version of them in the Camaro. It did not happen, although I bet that the engine codes were already assigned.

I saw an article in a magazine a couple of years ago about a '70 LS6 convertable chevelle that had aluminum heads. They even showed a picture of the build sheet to prove it.

I think I might have seen that magazine as well.I believe it was "Muscle Cars"

You all do realize that there is a direct linear relationship between the passage of time and the amount of dis-information that creeps into our hobby. If you think it's bad now, wait another ten years! By the way I've been to that place in Tarpon very nice big $$$ cars. My wife had her eyes set on a $41,000 60 'vette. Christ, now I've got to buy her a new couch as a peacekeeper after my tripower setup was done.

I recall seeing that article on a 1970 convertible LS-6 with aluminum heads...and yes they did have a photo of the car along with the protecto-plate ( i think...).
Anyways, it was part of some guy's larger collection and was put in the magazine to end all the speculation about a convertible with this engine. I believe the magazine was "Chevy High Performance" and was in an issue about 2-3 years ago.

I remember seeing this car (a '70 LS6 with aluminum heads) in a magazine. They also had a picture of a build sheet for it.

I would be highly suspicious of it.

As I remember it, the car was owned (at that time) by an outfit that sold/rented engine block stamping equipment.

I also have heard rumors that LS-6's could have come with aluminum heads. However, anyone buying an aluminum head LS-6 would not have gotten bench and column shift. If the protecto plate and build sheet looked fake, then it probably was. That's my 2 cents.

Pardon me, I could really be missing it, but I thought that the heads were one of the main things that made an LS-6 an LS-6, I would think that Chevy would have called it something else, mabey a ZL-2 or something. LS-7 are a crate motor, same as the LS-6, but 12.5 to 1 compression. I thought the heads were open chamber square ports. There is my best guess.

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RYAN REEVES
rreeves@lightspeed.net
http://www.geocities.com/MotorCity/Boulevard/6987/ryanreeves/reeves_main.html

The LS-6 as we know it for Chevelles had the same features as the L-78 396/402 and L-72 427. The only difference I can find is cubic inches. Please jump in if I am wrong.

The interesting thing I did find was that in 1971, for the Corvette only, there was another LS-6. It is listed as having large port open chamber aluminum heads, 9.0:1 CR, with all other specs as per a regular LS-6. These heads were the ones used on previous ZL-1 and L-88 motors. Sounds like someone did a swap from a Vette or pulled together the correct year parts. A good test for this car would be to yank out a piston and see if it is the 11 to 1 version. Then you'd know you had a fake for sure.

EDIT: On second thought, it looks like the CR difference may be in going from iron closed chambers to aluminum open chambers. Oh well.
John Walker

[This message has been edited by jmw (edited 05-26-99).]

jmw,
There are differences between the LS6 and L72,L78.The LS6 had stronger connecting rods similar to the L88 in design only with 7/16 knurled shanks.The exhaust valves are also bigger 1.88 compared to 1.84 on the L72.In 1970 both the L78 and LS6 had these exhaust valves.Also 1970 had the new aluminum low riser intake on the LS6 and L78.Previous years had an aluminum high riser.

I meant the exhaust valves are bigger on the LS6 not L72.My typo

I saw a car at a little show in the Tampa area a few years ago. It was supposed to be a real LS6, and the serial number started out 134xx instead of 136xx. Someone had also added air conditioning to it too. It was green, that's what picked my memory.
I remember reading about the LS6 with the alum. heads too One interesting thing I remember about the car was it had a fiberglass cowl hood, supposed to be factory, and also 15x7 Corvette style rally wheels.
The option code L89 only denotes the aluminum heads. It is possible the production numbers for L89 could include the LS6 too. Take for example the Corvettes that were built in the late '60s that were L71 tri-power cars with L89 alum. head options.
For 1970, the heads were cast #290 for both the LS5 and L34, and cast # 291 for both L78 and LS6. this pairing of engines led to a bunch of parts being the same between 396's and 454's.

Dave,
You have an excellent point!Perhaps the L89 option included LS6 motors as well as L78 motors.Good observation!

I agree that Dave makes a good point. An L78 396 when equipped with aluminum heads is simply an L89. An L71 Corvette with aluminum heads is also just an L89... I am still skeptical as to the production status of a legit '70 LS6 Chevelle with aluminum heads (whatever that makes it). L89/396 Chevelles in '70 numbered at just 18.