According to official sources, only 71 people-lucky owners of two Corvettes and 69 Camaros-were fortunate enough to get their hands on what was arguably the most powerful production car and engine package ever offered to the American public: the '69 all-aluminum big-block Chevy (http://www.hotrod.com/garage/hrdp_0211_gm_chevy_zl1_crate_engine/index.html#) 427ci RPO ZL1. A relative of that era's all-aluminum Can Am road-race Rat motors, the ZL1 was factory-rated at 430 gross horsepower at 5,200 rpm, but the actual output was nearly 600 gross horsepower after tuned headers were installed in place of the restrictive factory cast-iron exhaust manifolds. Although it technically carried the standard GM five-year/50,000 mile warranty of the day, ZL1s-with their 103-octane-guzzling 12.5:1 compression ratio, chokeless 850-cfm Holley double-pumper carb, blocked-off distributor vacuum advance, and huge mechanical-lifter camshaft-were really intended for racing only. They didn't idle, low-end response was nil, you didn't drive them to a family picnic, and you sure as hell didn't sit in rush-hour traffic. But, hey, those were the '60s.

http://www.brightcove.tv/title.jsp?title=1586321544&channel=340485641[/URL]

This is one of my favorite pictures. It was taken one evening at the Holiday Inn located in Rockingham, NC. They are removing the transmission which they had just broke racing. The transmission was rebuilt in the hotel bathtub, using Holiday Inn towels as shop rags. Those were the days !

http://i144.photobucket.com/albums/r185/185sport/holiday.jpg?t=1228872171
More ZL1 Stuff
True HP.
http://corvette.luxurysportsautos.com/the-zl1-corvette (http://video.google.com/videosearch?hl=en&q=1969%20ZL1&um=1&ie=UTF-8&sa=N&tab=wv)
[URL]http://www.popularhotrodding.com/tech/0801phr_zl1_aluminum_big_block/index.html
http://www.sdkgarage.com/carpix/assorted/zl1.html
http://www.superchevy.com/features/camaro/sucs_0707_1969_chevrolet_camaro_zl1/index.html
But back to the task at hand, the 1969 ZL1 Corvette, this was probably the wildest production car ever built, the Zl1 engine was an all aluminum 427 CID big block Chevrolet, and this cut about 300 pounds off the weight of the car, so you can imagine what that would do for it’s ¼ mile times, the engine was rated from the factory at 430 hp, but actually made about 625 hp on the dyno, and a 1969 Corvette was around 3200 pounds, this would mean that the car was capable of about 11.18’s in the ¼ mile. In street dress, I don’t have a time with open exhaust and slicks on the car, but you could probably add about 1 second with a good driver.
This car was built to impress, and that it did, there were a white ZL1 and a yellow one built, in I think it was 1989, if I’m not mistaken, the government seized the yellow one in a drug raid, in which the owner went to prison, they proceeded to auction the car their estimated value of the car was $500,000, but they sold it for the minimum reserve of $300,000 to a very lucky winner, and the white one I’m not sure where it is, but it’s out there somewhere, now you hear the Ford guys and the Mopar guys tell you all the time, how their cars beat down the Chevy’s, but not this one boys.
http://www.rogerscorvette.com/inv/special/69ZL1/index.htm

Kevin Suydam out in Seattle has the white ZL1 'Vette...and I believe Motor Trend or someone did a test of a ZL1 'Vette set up for the drag strip, and it was deep in the 10s if I remember right, I'll see if I can find my copy.

Some people say there were 2 ZL1 Corvettes others say 3

A yellow, white, and orange one claim to be real ZL1s

http://www.corvettefever.com/featuredvehicles/corp_0603_1969_chevy_corvette_zl1/index.html

http://www.autofacts.ca/classics/FAPC/ZL1Corvette.htm



Chevy had a few ZL1 test cars but these are not counted as production.

They had one set up for drag racing that ran in the 10s

Zora D had a white one set up for road racing he used for testing

They are shown on this site.

here they say the drag car was a red Corvette but other magazines said it was orange.

http://www.corvettelegends.com/zl1.htm

quote "ZL1s-with their 103-octane-guzzling 12.5:1 compression ratio, chokeless 850-cfm Holley double-pumper carb, blocked-off distributor vacuum advance, and huge mechanical-lifter camshaft-were really intended for racing only. They didn't idle, low-end response was nil, you didn't drive them to a family picnic, and you sure as hell didn't sit in rush-hour traffic. But, hey, those were the '60s."

I agree the ZL-1 is the most powerful of all musclecars, however I feel I must correct some incorrect information before it gets repeated thruout history. The ZL-1 has 12:1 compression, not 12.5:1. The camshaft has 262/273 duration at .050" yet it has a wide 112* LSA that allows it to work ok on the street. My ZL-1 idles quite fine (at the factory spec 1000 rpm), and has plenty of low end response above 2000 rpm. I drive mine to the car shows, some as far as 60+ miles away (I would not want to sit in rush hour traffic though). Although not a factory installed ZL-1 engine, mine is built to exact factory specs using all NOS GM componants, so I am speaking from first hand experience. It is a monster!

A year or so ago there was talk of a 70th ZL1 Camaro in Canada with GM Canada paperwork. Supposedly Zappora knows of it. Anybody have any more info ? Rumor ? Truth ? I heard it was Yellow ?

That is a cool picture of ZL1 #1 at the hotel. Taken when it had the "Dick Harrell" stripe paint job.

Some of the DH street cars also had this stripe.

The car was restored with the earler paint job.

Interesting that on the console plate the ZL-1 option is the only one that leaves the horsepower, torque & compression ratio blank.. Here is a NOS ZL-1 tag for a Corvette shown next to one for an LT-1 for comparison. http://i248.photobucket.com/albums/gg163/nhbandit/100_1802.jpg

ZL1 #1 is one of my favorite cars. It is currently owned by a very good friend of mne so I have access to the car at anytime. I love sifting through the the paperwork and studying the car. I can just sit there for hours. I only wish I had the coin to own it!!

Mark,Very kooool, thanks for posting them!! Dan

No stock ZL-1 made 625 hp on any dyno. Current restoration engines are in the 525-550 hp range, with headers. Bill Porterfield did an 'as-installed' run way back when; 375 hp.

BTW the engine picked up over 80 hp when the so-called "high-performance" chambered exhaust was removed.

William I notice ZL1 #1 has a spoiler along with #2?

http://images.google.com/imgres?imgurl=http://www.zlx.com/camaro/zl1_2000.jpg&imgrefurl=http://www.zlx.com/camaro/zl1.htm&usg=__zcE-PYOn6694GyF_R8-ZObV9kSQ=&h=251&w=500&sz=38&hl=en&start=39&tbnid=ATtlbSwhwm2LGM:&tbnh=65&tbnw=130&prev=/images%3Fq%3DZL1%2Bhorsepower%26start%3D20%26gbv%3 D2%26ndsp%3D20%26hl%3Den%26sa%3DN

http://hotrod.automotive.com/81516/hrdp-0211-gm-chevy-zl1-crate-engine/index.html

http://www.fast-autos.net/vehicles/Chevrolet/1969/Corvette_ZL-1/

http://www.superchevy.com/features/camaro/sucs_0707_1969_chevrolet_camaro_zl1/index.html

http://classicchevrolets.com/copo_camaro_history.php

William I notice ZL1 #1 has a spoiler along with #2?

Not from the factory. All Gibbs' ZL-1s were identically equipped: 9560, an optional transmission [30 M-21, 20 M-40] F70 x 14 RWL tires, power front disc brakes. That's it. All had black standard interior.

M-40s were column shift. Try finding parts for that today.

No stock ZL-1 made 625 hp on any dyno. Current restoration engines are in the 525-550 hp range, with headers. Bill Porterfield did an 'as-installed' run way back when; 375 hp.

BTW the engine picked up over 80 hp when the so-called "high-performance" chambered exhaust was removed.

Chevy dyno sheets from back in the day show 580hp (Ed Cunneen) and I believe it. Chambered exhaust is like potatoes in the pipes for these engines. At least loses of 80hp, more like 100+. Flowmasters work real good!

Flowmasters work real good!
Sorry, but Flowmasters SUCK...I wouldn't give you a nickel for every Flowmaster muffler on the planet...we went from NOS chambered to Flowmaster to Pypes transverse and picked up serious MPH with each upgrade...as an fyi, the ZL1 & L88 engines in the Pure Stock class I run in are making over 500 hp through stock exhaust manifolds & with factory blueprint cams.

Chevy dyno sheets from back in the day show 580hp (Ed Cunneen) and I believe it. Chambered exhaust is like potatoes in the pipes for these engines. At least loses of 80hp, more like 100+. Flowmasters work real good!

"Chevy" dyno sheets?

You need to learn how Chevy did dyno tests in those days. 114 octane fuel, unrestricted intake and exhaust, no accessories like a coolant pump, fan or alternator. Porterfield has done a few and CHP just rebuilt 2 OE ZL-1 engines. 525-550 hp under "real world" conditions.

Did any of the ZL1's actually have a chambered exhaust from the factory? I would think the ZL1 would pick up 80-100 hp by removing whatever exhaust was installed.

Of the 19 non-Gibb ZL-1s only #59 N642876 is known to have been built with NC8 via factory paperwork.

Paperwork for 7 others shows they were not. There is no paperwork for #3 but vintage chassis photos taken for the Aug 69 CARS road test shows the standard muffler/resonator system. By the time #68 and #69 were built NC8 was no longer available. How the remainder were built is unknown.

The original ZL1 engine was not that strong of a block. The drag racers had problems with HP loss due to piston/ring sealing problems from the block "moving". At one time Bill Jenkins hooked up a block heater to his and kept the engine hot in the pits to try to keep the engine making consistant power.

The L88 engine was almost the same as the ZL1 except used the iron block and was a better engine for making HP.

To address this problem, Chevy re-designed the alum block to make it stronger and came up with the "CanAm" block.

I have not seen a good article on the race history of the original ZL1 engine. It would be difficult to put together because some people like Bill Jenkins switched engines a lot and used the ZL1 and L88 engine on the same race weekend.

In Pro Stock (1970) the Can Am block was legal so was used by some, the original ZL1 engine and the L88 engine were both legal in Super Stock.

I have heard that the ZL1 #1 used the L88 engine in 1970-71 when it won many races.

A few guys did stick with the original ZL1 engine but most didn't

http://www.guinns-engineering.com/Wetherall%20ZL1%20Casting.htm

I am not sure what they are talking about in that link. They are calling the ZL1 engine a CanAm engine because it was used in a CanAm race but that is confusing.

The ZL1 block was used in early CanAm race cars but that was not what most people call the “CamAm” block.
The “CamAm” block came out later then the ZL1 when Chevy developed a new stronger large bore block design with Siamese cylinders. There were a few versions of it. One used cast iron liners and others had no liners.

It looked similar to the zL1 but the “CamAm” block was a different casting design.

Here is some info from a google search on the CanAm block………..

Service only - 4.440 bore 356 alloy with cast iron dry cylinder
liners. Built in 1969 to 1972 as bare cylinder block only.
Standard displacements are 430 CID with 3.47" stroke crank,
465 CID with 3.76" stroke crank, and 495 CID with a 4" stroke
crankshaft.

Service only - 4.440 bore 390 alloy with no cylinder liners
[pistons run directly on cylinder bores and must be iron plated
for compatibility] This engine was available as a bare cylinder
block only starting in 1972. Due to piston availability, the engine
can only be built as 430 or 441 CID [with a .060 overbore], and 495
or 510 CID [with a .060 overbore] using 3.47" or 4" strokes respectively.

Found this cool post from a CanAm race site talking about the engines…..

""I was an engine builder for the UOP Shadow Team from 72
through 75 and built these engines almost exclusively.
Engines I assembled were driven by Jackie Oliver, George
Follmer, Vic Elford, James Hunt and Peter Revson. I was
trained on them by Lee Muir who came to Shadow directly
from McLaren. I've got loads of photos and, if I dig deep
enough I can probably dig up my track/tuning notes.
In the early Can Am years only three teams had the Reynolds
"390" Aluminum blocks. McLAren, Shadow, and Chapparral. Later
they became more common, but most of the "lesser" teams didn't
use the all-aluminum 390 blocks, but iron sleeved castings.
All were Lucas injected.
McLAren did their own porting, as did we. The usual well known
California head guys did most of the rest.
We rarely built 510's, almost always 495's. Race trim hp was
about 735with flat tappets. We bult some roller tappet "Qualifyers"
that did about 775 hp. In '73 we built a 1200 hp turbo 495
(I could change those head gaskets in my sleep!) to compete with
the 917K. We were faster at Laguna Seca but ran out of brakes.
Vic Elford was driving- Donohue came over to Lee and I after the
race and told us "he'd NEVER seen anything accelerate up the hill
like that beast". THe tires on that car were 24 inches wide and it
would leave giant blackies all the way up the hill. I've built lots
of engines but those are still my favorite. Nothing in motorsports
sounds like 20 of those things at the green. I'll never forget it.""

also found cool picture of a 67 Camaro and a Chaparral

Looks like the Joey Chitwood Camaro at Daytona

Nice pic joe58 :D

Since were on the subject of ZL1's I need to ask this.Bought these from a old dragracer from the 1970's. Have a complete set of them. The pistons are Stamped TRW and L 2308 A 060 on the dome with C 252-97 casted underneath. I know the L2308 is 427 ZL1,but what does the C 252-97 mean? Are these the same pistons used in the L-88 427 motors? Thanks!

Were'nt there some "C" codes on chevrolet engineering test parts? I seem to remember some blocks with silimar codes and a discussion about that. Thoughts William, or am I off base?

Rich

Some engineering ZL-1 stuff did get out. Tech Center parts typically had "0-XXXX' part numbers.

Initially only Jim Hall/Chaparral received prototype aluminum bb stuff and he typically did not sell his old race cars; still has most of them I believe. The program was later expanded to include McLaren, the likely source for the few pieces out there. Bill Jenkins is said to have received a block in '67 or thereabouts; don't know what he did with it.

Our business did a ZL-1 Camaro years ago. The production block we used came from La Mar Walden via McLaren.

Did any of the ZL1's actually have a chambered exhaust from the factory? I would think the ZL1 would pick up 80-100 hp by removing whatever exhaust was installed.

According to Fred Gibb, the first 2 ZL1s had chambered exhaust from the factory

According to Fred Gibb, the first 2 ZL1s had chambered exhaust from the factory

Documentation for both cars exists and does not list NC8 as an option. It was not included with either COPO.

Some engineering ZL-1 stuff did get out. Tech Center parts typically had "0-XXXX' part numbers.

Initially only Jim Hall/Chaparral received prototype aluminum bb stuff and he typically did not sell his old race cars; still has most of them I believe. The program was later expanded to include McLaren, the likely source for the few pieces out there. Bill Jenkins is said to have received a block in '67 or thereabouts; don't know what he did with it.

Our business did a ZL-1 Camaro years ago. The production block we used came from La Mar Walden via McLaren. Lots of cool stuff out there if you know what to look for. A good friend of mine a few years ago poking around at the swap meet in Englishtown NJ bought a set of 0- part number bigblock aluminum heads with 1965 casting dates

Yep, that was it, the "O"- codes. Sorry for mis info!
:)

Rich

Documentation for both cars exists and does not list NC8 as an option. It was not included with either COPO.

I don't know how accurate Fred's memory was but in his 1990 interview he was asked about ZL1 #1 and #2.

One of his comments was "they had duel chambered exhaust, and it was loud"