A coworker is arguing that the LS6 454 only came factory installed in the chevelle, and that it was an iron head engine. Also, that the ZL1 was a 454.

My position is this:

Corvette came with the LS6 at least in 1971 and I think in 1970, had aluminum heads and a lower profile intake manifold to fit under the normal (non-l88) bb hood.

The ZL1 was essentially an L88 with an aluminum block, and was a 427.

The LS7 was an all aluminum 454 that never made it into a production car but was slated for the vette for '71.

I need some references to substantiate that he's wrong, or that I'm wrong. He says his info came from chevy power.

 

http://corvetteactioncenter.com/spec...70/70prod.html
http://corvetteactioncenter.com/specs/c3/1970/70id.html

http://corvetteactioncenter.com/spec...71/71prod.html
http://corvetteactioncenter.com/specs/c3/1971/71id.html

Does that help?

 

1971 option, installed in 188 Vettes plus 12 ZR-2 optioned competition packages (like L-88 with big brakes, no radio, no BS!) Early Shark on this forum owns 2 LS-6 Vettes and a friend of mine just bought 3 LS-6's from Canada with one being a ZR-2 package (he told me one was traded into a snowmobile dealer on a new "snow machine" as Sara says.) In a race my $$ would be on a 71 LS-6 Vette racing a 70 Chevelle LS-6 but I would rather own a L-88.

 

"ZL1 was essentially an L88 with an aluminum block, and was a 427."
Yes.

The LS7 454 was not all aluminum.

 

Your co-worker is wrong, but you won't convince him to change his mind.

The ZL-1 is not an aluminum L-88. It's 427 CID but the block is a completely different casting.

As far as Chevy Power goes, just because information is printed does not make it correct.

 

I had an LS6 engine out of a 70 Chevelle (CRR code for Turbo 400 tranny) in a 70 Corvette hard top. It was rated at 450 hp; it had rectangular port iron heads, Hedman headders and a big Holley. It had bad brakes, a rebuilt turbo 400 and tall rear tires. It ran bad; then my mechanic brother replaced the throttle cable. This car was flat-out dangerous. I went Viper hunting. It got about 6-8 mpg, maybe 4 if I had my foot in it. My 68 L36 Roadster is tame in comparison.

 

I would offhandedly call a ZL1 an aluminum L88 as it has the identical components as the L88. The only difference between the two is the material the block is made of....{ie} aluminum verses iron....

The LS7 454 is a different story. 1/4 point lower compression at 12 1/4and pressed pins instead of full floating was all iron...only available as a over the counter off road engine...and was not complete lacking some of the bolt on stuff ....intake, distributor,.exhaust, water pump, flywheel and clutch were missing and no bell housing....none since around 1988-90 as the engine was allowed to sell out

 

I haven't looked into the over the counter LS7 engines, but I thought there were 4 or 5 'LS7' engines built and planned as the highest hp option for the 70 or 71 vette but it never materialized.

I may be wrong about all aluminum, but I remember reading somewhere that the fastest 1/4 mile time recorded for an L88 in a magazine was actually a 69 vette with the LS7. I'll see if I can find a link to what I am talking about. Thanks for the help.

 

ZL1 is an aluminum block, aluminum head 427 made in 1969 only. It shares many components with the L88 from the same year and are different from the 1967 1968 engines. 1969 has an 074 aluminum open chamber head and pistons, 7/16 rod bolts, and the ZL1 cam specs are different with higher lift than the L88 cam. The ZL1 was the baddest of the bad in my book with the weight savings and engine specs even the L88 was a little tamer. They were all 12 1/2 to 1 compression. I built a numbers matching 1970 LS6 (chevelle only) a couple years ago. They were rated at higher HP than the ZL1 or L88 but were a little more srteetable due to a less radical cam and slightly less compression (11.25 to 1) with more cubic inches. Iron block, Iron heads only. The intake held these back as they were a low rise for the corvette which it was not installed in. All of these really needed headers to reach their full potential. A better intake would have helped also. The 1971 LS6 in the corvette was a shadow of the former engines. It was an LS6 in name only and I look at them as a marketing ploy to ride on the reputation of the 1970 LS6 chevelle gained at the dragstrip. Same low rise intake as the 1970 LS6. Reduced compression (9.0 to 1) smaller cam. much more streetable. It had the same heads as the ZL1 but was not even close to the race only manners of the ZL1/L88. The LS7 was planned in 1970 to end up in corvettes as a 454 version of the L88but GM corporate, the insurance industry, coming changes in fuel, emissions and the end of the muscle car era turned the LS7 into a crate engine only. Iron Block, Iron heads, Some similar specs to the 1970 LS6 but higher compression and I believe they had the higher lift ZL1 cam. These were a true race engine also but I believe the later models reduced compression and cam specs.

 

LS6 never had aluminum heads.

Sounds like both of you have some correct and some incorrect facts.

 

http://www.idavette.net/facts/71.htm


LS6


454ci 425hp Engine


188

 

Just adding a few facts....

Chevrolet intended to market the LS7 in the 1970 'vette. I have some re-prints from automotive journalists doing their write-up - primarily the April 1970 Road Test magazine "'70 Corvette is more late than new" where they drive the 1970 Corvette outfitted with a 460hp 454 engine at Riverside Raceway in California. I can't see where they call it an LS7 - simply describing it as a 460hp 454 v8 engine.

There's also the "1970 Plus" article in March 1970 issue of World Car Guide that lists a 454-CID V-8 at 460hp.

 

It was also offered in the El Camino

 

1971 Corvette LS6 used Head # 3946074 according to Corvette By the numbers by Alan Colvin. They are aluminum and the same part number used on the 1969 L88 and 1969 ZL1.

 

Right! I forgot that. A local guy here has one.