n2h2o2

Wow....just WoW! lol
The physics of flame fronts....trapped pockets = gas bomb= big boom = piston shrapnel! LOL...
These engineers were pushing the very limits of ICE at that time....
This thread is covering it all!... I love it!

TCracingCA

The Chaparral pre-ZL-1 Aluminum Big Blocks were an internal Dry sump system, I might be one of the few that has drawings on that, and I shared some of that in a thread years ago here on the Corvette Forum. Essentially Bill Howell shared that when they did the ZL-1, I am seeing that started in 1968, his quote, "we were trying to take what was developed for a Chaparral Big Block engine, and turn it into a production racing engine". Anyone with like some of the good Can Am books will see what is referred to as a Chaparral customer engine installed with other teams showing in pictures, but this Chaparral unit was actually Chevrolet units. The acquaintence with McLaren himself, started just right at the beginning of 1968. The selling of these aluminum internal dry sump engines was a decision related to Vince Piggens, and Jim Hall wasn't too happy to have assisted in development to have Chevrolet deciding on an even playing field. Thus this is when like Penske's team came into the picture. Initially McLaren learning of the Chevrolet Big Block support to Hall, he threatened to go with Ford engines (the SOHC was out), and so that meeting with Chevrolet happened. In 1969 the Chaparral named engines essentially phased out, for the new available Chevrolet branded ZL-1 customer racing engine. I can pull the Dry sump internal stuff out again, but you could probably do a search and Rex L88 won the contest I had, for identifying what I was sharing with everyone. One member was close, but just did not type Internal Dry Sump, so I named a Co-Winner. I think that was in the big Southern California slalom thread, where I delete near 200 posts, as a certain couple of people pissed me off, but I have 100s of posts still up in that thread.

A second evolution of the ZL-1 that causes confusion with anyone except for me! place smile here, is that is confused with the coming Reynolds 390 Can Am engines, Chevrolet offered a second generation ZL-1 offered just for one year only, the steel linered/sleeved 4.40-inch bore which I talked about previously in this thread earlier, the punched ZL-1, getting to 8.1 liters or 494 cubes.

leigh1322

I remember being at the Daytona 24 hours in 1970.
While we were sitting in the top row of the stands I heard another nasty engine, and it came from the parking lot!?
Directly beneath me was a Medium Blue 1970 RS Camaro, with a single custom body stripe down the scooped hood, which was very odd because that car was a brand new model at the time, it was only out a couple of months.
The other thing was that it sounded louder and nastier than all the race cars on the track, It made the wall vibrate straight up to where I was sitting.
And it was parked right by the wall, right by the main gate. Obviously someone very special.
A few years later I saw that car again in a Camaro history book.
It was an all aluminum ZL1 1970 RS Camaro built especially for Bill Mitchell, VP of GM styling at the time.
I can still "hear" that thing growl & roar, over the race cars.

TCracingCA

People just love their domed pistons, bless their hearts!!!!!!

I build my two all aluminum SB engines for my Corvettes on long rods and flat tops, with smaller 55cc combustion chambered Phase 6 23 degree heads is my formula. I run a whole shitload of 40+ advance, and high hitting ignition systems, but that might be a show and tell thread for the future.

Old picture in front of one of my research library book shelves.

TCracingCA

I think where they went wrong, Orange crowd fan boy club, was the 1969 L88 automatic all 17 of them, and L88 being the basis for order related to getting an ZL-1 confuses these guys. Thus discounting that L88 engine no longer there, as an ZL-1 was substituted. Thus created a true bastard inaccurate Restoration using Closed chamber heads while claiming Zl-1, thus we need to wear our high boots, as the bullcrap gets deep!

n2h2o2

Now we are talking my language...I like where you are going with the flat top, small chambers, long rods...LOTS of good reasons I can think of over domes....Unless it has a hemi aspect to it...But don't want to go there...lol
Reminds me of the 302 Chevy screamers we built for Pro-Stock...You didn't use a 283 crank with 327 pistons with your long rods did you? lol

TCracingCA

Wet Sump GM Bowtie block, but might put my Dry sump back on this one, 3.50 straight up crank grind, 4.060 bore (even though I could go way larger) for 362.5 cubes. GM raw forged 4340, oversized fillets, big block snout, Bowtie profiled rods, but have some Carrillos too, Stainless 1.6 rockers, Max ported heads, Ross Pistons, tool steel pins, tool steel lightweight retainers, Inconel exhaust valves 1.6, stemmed hollow stemmed intakes 2.05, 140 GM Cam, Bowtie Aircap single plane, 850 Holley, 4 inch Collectors, etc. etc. etc.

My other one is 3.48 x 4.030 for 355 cubes

Car specs in my forum profile.

TCracingCA

I think I have a picture somewhere of that car. But will search internet to see if it shows, before looking through 100k pictures.

Vette5311

Of interest, in case you missed it, Dec issue of HotRod had a reprint of the original ZL1 article in honor of their 75th anniversary.

DarrellD23

I just want to say thank you to everyone posting on this thread. I have learned so much about the ZL1. I was so intrigued that I had to go to Florida on Wednesday to personally visit the yellow car. It's was great to see the ZL1 in person. Being a corvette junkie and seeing the holy grail car is about as good as it gets. My son and I were the only people in the dealership and they let us go behind the ropes and inspect it up close. A great corvette moment that we will never forget. Thanks again for all your great input and keep it coming!

DarrellD23

TCracingCA

Glad we inspired this idea of a visit. Most woman probably won't understand an excursion like this. Pick a destination to see a car or a much of cars, par it with a super great restaurant, spirited driving roads, and scenery. Then someone will go to a museum and see a bunch of impersonal old stuff, and call it a weekend.

I do see guys are following his, and I wish I was a better writer, as my post are research shares. I might like in my Rare Car Enthusiast Registry thread in C2, try to better catalog this stuff with best authored posts eventually. I was working my way toward C3 history. As many know, I struggle to find time for this stuff. Today watching the Mecum, the NART Ferrari just crossed, the 1967 Red/Red L88 earlier, no sale, bid to 2.7 million.

One day I will better and more thoroughly write and then share this history. But an example is I pretty much have figures out like the 1966 HD/M22 history. Other than the prototype, mule, testing & development cars, they decided to build 12 Service test cars. What people think, is these were proving ground or test car, but no! The 12 were the cars that went out the door to include the ones I share on my Registry listing- The racer kits that went out to select dealerships. So these in the hands of the Dealerships, select outfits became the test fleet, using the race tracks as the test tracks. GM Head Donner who was the proponent of enforcement of the 1957 AMA racing band, had his merry men of hall monitors ensuring that no department was leading the Press, etc. in believing Divisions of GM were directly involved in Factory Racing. Many like Estes who took over from Bunkie, liked Knutsen's plan. Allowed Zora to filter out kits, a few built up cars related to the 1966 back door racing support starting with Penske at Daytona, appearance at Sebring all private hand appearing race entry. They got wind that Mr. Donner was planning to retire 5 years early, end of 1967. Thus they filter out cars for 1967, thus accounting for only 20 of those, but getting the support for runs at Sebring, LeMans, and then appearance at 1968 Daytona. Naturally they did not know who was going to be the next GM Head guy, and the selection was generally done in private for that. Thus the 1968 model was hoped to be their new day, if the right GM guy ended up in charge. They geared up for an all out race car supply, an actual 100 cars built for true homologation. The parts were put into the new GM Performance/Counter Supply for the customers to race modify these L88s to be made available.



Since this thread is drawing out posts from me, now venturing more seriously into C3. Some cataloging would be:

1967- That C3 car with the reach in door pulls, possibly silver with Zora sitting inside, driver's helmet on, side piped car was essentially the L88 mule. Zora talking to Estes.




1967- The dark car with the headlight buckets, side pipes, AR mags was the L88 Homologation car.


1968- We had the 1968 with the ZL-1 mule!


Zora with Henri Greder, and Racer Marie-Claude Beaumont in France.


ZL-1 Homologation Car, was one of Zora's engineering prototypes which he used for more than a year.


I am glad people are enjoying this thread.

leigh1322

I pretty easily found a pic of the ZL1 Camaro from the book.



I probably saw it at the 71 Daytona 24 hour race on Jan 30. The 70 Camaro was released on 2-25-70,a month after the 1970 24 hour race, so it probably wasn't at the 70 race. And by 71 we already owned one at home, I was 16 and driving, and that blue one really got my attention compared to the 307 one we had at home!

XXvette

I don't know.
There has always been some spec that a white T top ZL 1 existed. Myabe this owner didnt know enough about the car but needed the sell.
Not many cany pony up 150K on ebay
It is going to show up in the future if it was the real deal. Y ou have to be able to go look at the car directly....And if it was ... someone hit a home run.

Vette5311

I had always heard rumors that a white T top with blue stripe and tail was a 3rd ZL1, but always just thought it was an urban legend.
Anyone else ever heard of this car?

FastCarsNMeanGuitars

ZL1
Bill Mitchells Baddie in Color

charliedents

Yesterday in Pittsburgh, there was an estate sale that had 4 new ZiL1s still in the crate. Lots of other stuff was there also including a couple race 69 Camaros and a 2014 or 15 COPO roller. It was pretty convoluted the way they did it but some fellow walked in at the very beginning and offered 400,000 for everything in the shop and apparently the estate sealed the deal and the rest of the estate sale was closed. Look up Kunsak on facebook. I tried to copy and paste the link, and for some reason I couldn’t not.

n2h2o2

I am not sure if this is the same car, but there are models of a white car with blue stripes and it is called a "Test Car".
I believe this car was kept by Zora at the GM proving grounds for several years as a test mule.

DKM-106

The ZL1 in this auction is not originally a ZL1 form the factory, it was most likely a L71.

DKM-106

I haven't heard that rumor. In my opinion the yellow coupe was the first to leave the factory as an RPO ZL1. I also believe the second ZL1 was most likely built in October.