Hot Rods The 1963 Chevrolet Impala Z11 factory lightweight car

Found this cool article on these historic cars.
Anyone ever have the opportunity to actually touch one of these near unicorns?


"The 1963 Chevrolet Impala RPO Z11 Is Super Rare: Only 57 Cars Ever Built, And Only A Handful Remain".
https://www.hotcars.com/1963-chevrolet-impala-rpo-z11-facts/

 

We always wonder who writes these articles.
https://www.hotcars.com/1963-chevrolet-impala-rpo-z11-facts/

 

I can't vouch for the "facts"!

 

Millennials who superficially google it then write the story...

This one is more accurate than most. Their Torino Talladega story was terrible...

 

I was never allowed to touch the couple that I saw. I was about 10-years-old. They were afraid that I would dent them. The acid dipped car guys told me the same thing.

 

We have a red 62 Impala SS here in Wi. that the owner claims, it is a "Special order" drag car, BBC but not with 409 valve covers, rectangular covers like 396/427 from GM. Fact or fiction ? I always hear stories at the car shows about the special, rare, one off factory cars, usually for sale for big bucks. We all know if BS was brass, a huge brass band is always available at any car event. LOL Side Note, I know a man here in Wi, that has a 63/64 full size Ford 427 side oiler, 2x4, fiberglass bumpers, the huge cast iron exhaust manifolds, super plain jane interior, radio, heat delete drag car, I'm not an expert on these cars, he tells me he purchased it new, he's 80 this year so it's possible IMO And he still drives it on the street some local cruises/shows, I tend to think this one is real, one reason being it's not or ever been for sale I'm told.

 

Z11 409 engine.


427 Mystery engine.


https://macsmotorcitygarage.com/inside-the-63-chevy-427-mystery-engine/

 

Since I was looking a lot into artificial intelligence stuff (job related) and also had quite a time to play with it, the article looks very AI generated to me.

Frank

 

I have touched both of these.



Got the honor of making a parade lap around the pits in the Jackshaw car.
It was converted to Z11 car at Dyno Dons shop.

 

I see a couple pics in here with S/S on the car.

I'm trying to figure when, circa 1963-71, these cars were NHRA Legal in Stock or SuperStock.
I know they ran in L/P in 63, then AFX, but did they ever run in NHRA S/S or AA/S class?
Why where when or why not?

 

I'd say it's BS since Chevrolet engineers were just working on the MkI version in 1962, which debuted at Daytona in 1963 as the MII 427 engine and nobody had seen or heard anything about the new Chevy Big Blocks prior to 1963!
Here's a well written history of the Chevy Mk engines, or as they called them then the "mystery engine".
https://www.motortrend.com/how-to/sucp-0607-mark-iv-big-block-chevy-engine/

 

1963 The 427 Mystery engine cars were made available for successful NASCAR racers while the 427 z-11 W motor became available to successful drag racers, Ford did this with the 427 Thunderbolt Fairlanes in 64 and later sold them to the racers for very little money, Malcom Durham pulled the 427 z-11 drive train out of his 63 and put it in a lighter weight 1964 Chevelle to remain competitive.

 

Z 11 were 427 cube. I don't know if any other W stuff would interchange. Local guy had one at 484 cube, 454 crank. Some body was building him a alum block, don't know if it ever got done, haven't seen the car or him for a long time.

 

I remember way back when I was looking to buy a Z-11 intake, from air cleaner to intake manifold. That was until I was told the price. I had the air cleaner assembly in my hand...I carefully put it back on the table, and thanked the guy for the offer.
It was more money than most complete cars, including my 61 Impala with a 421 inch 409 in it !

Yes, this guy DID have a true Z-11 sitting in the garage. Bumper to bumper.

As you might imagine...I did without.

Mike

 

Most of the stuff could swap to a standard 409 block as they used the same casting number block for all versions of the 409/427 in 1963, but all the other parts had unique part numbers, so there would be some not so visible differences. The heads are the same valve sizes as the 409hp/425hp 409 motors. I would guess the runners and maybe the iron used might have been different, but they would swap onto a 409 block. The intake manifold is the most unique to the Z-11's 427 as it was a 2 piece unit. They did get a aluminum water pump vs cast iron, but they would swap back and forth.

 

I sure dig the cowl air cleaners!

 

Knowing their pedigree I have to agree.
Glad I'm not looking for one!

 

All I found digging around today was
NHRA Minimum Production to run in Stock or S/S
100 for 1962
50 for 1963, but raised to
100 sometime during 1963, not sure when
100 for 1964 but then lowered to
50 during 1964 (so the 64 Lightweight Gal & 64 Hemi cars only needed to make 50 each)

By Pomona 1963, 50 Z11's were build so they should have been legal & therefore grandfathered in, although one source says only 49 built so maybe they didnt make it.
Or, the minimum had already been raised to 100 by Feb 63 Pomona so the Z11 did not make it, never even close.

Any other urban legends or knowledge welcome.

Just doesnt seem fair the Z11 never ran in NHRA S/S or AA/S, but then why do some of the cars have S/S painted on them?

 

My late friend told me he took these z-11 pictures at an Illinois track in 1964,
the name on the hood looks like Ugly Duckling, anyone remember this car?
It's got S/S on the windshield

 

Nice thanks!
Looks like an I/S 57 Chev behind it which would be a 283/220 wagon in 1964 class.
And a 64 plymouth back there too? Newest car I see, so many old ones.

A) So if this is NHRA, let's say it was early 1964, and AA/S=7.00 class didnt exist yet.
So the Z11 ran in S/S, against the Tbolts, that might get kinda ugly.

B) Or was it later 1964, when AA/S=7.00 class did exist, but the Z11 was factored so high that it was bumped up into S/S? Running against the Tbolt and the new Hemi. Those cars were factored to about 500fhp.
The Z11 would have to be factored to at least 480fhp to get bumped up out of AA/S=7.00 and into S/S.
If so, that would explain why we wouldnt see too many, not gonna compete well vs the Tbolt or Race Hemis from late 64 on up.

I wonder if its story A or story B?
I'm thinking Story B since it seems there are no pictures or history of the Z11 ever running down in AA/S=7.00.
Still seems kinda unfair, AA/S is where it belonged.

 

On you tube there is some info on the z 11

 

The Ugly Duckling may have run at an outlaw track, one that was not sanctioned by the NHRA, or AHRA for example. That could explain the S/S designation.

 

Agreed, we see a car in 1964, S/S on it, but maybe it was an AHRA track or maybe a local track that allowed stuff not formally allowed by NHRA. But let’s say these 1964 pictures are truly NHRA, and the Z11 legal in S/S. Then why wouldn’t we see it in the outyears?

A) The Z11 might have been illegal in 1963 S/S if the Production Minimum was Pmin=100, since only 57 were built. It seems that sometime during 1964, Pmin was lowered from Pmin=100, when the Tbolt appeared, to Pmin=50 later in 1964 when the Lightweight 427 HiRiser Galaxie (P=50) showed up, along with the Hemi Dodge (P=55) and Hemi Plymouth (P=55). Maybe NHRA cut the Z11 some slack and said “well ok theres only P=50 or 57 Z11’s but we will let it run since Pmin=50 now”. Awesome! So we might see the Z11 in 1964 with S/S on it.

B) But why S/S and not AA/S=7.00 by later in 1964? Seems there are no pictures of a Z11 with AA/S on it. And yet, the Z11 lands in AA/S=7.00-8.69 whether factored at 430hp or even 475fhp. NHRA would have to factor the Z11 all the way up to 480fhp to bump it up out of AA/S into S/S. It’s starting to look like they did just that though I’ve never seen it stated.

C) And it gets even worse: The Z11 has 3341/427=7.82 lb/CID. After 1964, NHRA Rules had a minimum of 8.00 lb/CID to run in S/S or later SS/A, which booted the 64 Tbolt and the 64 A864 Race Hemi off the track. This same rule would make the Z11 illegal in S/S for 1965-66. The Z11, if factored at FHP=480 for W/P=3341/480=6.96 to keep it out of AA/S, would still be illegal for 1967 since it would fit SS/A=6.00-6.99 class, and would then fail the Minimum 8 lb/CID rule for SS/A.

D) The Z11 could reappear for the 1968 season in SS/B=6.00-6.99 class against the 65 A990 Race Hemi or the 68 Race Hemi Dart/Cuda. Even if legal, it seems no surprise we wouldn’t see them return to that kind of welcome.

E) For the 1969 season, the Z11 was aged out of SS due to the 5 year rule.

To conclude, if the Z11 was ever legal, in spite of its production of only P=57, we should have seen it in AA/S=7.00 class at W/P=3341/430=7.77, but we don’t see it in AA/S, ever.

So *if* the Z11 was legal, since we only see cars marked S/S, and only in 1964 (so far), we have to tentatively conclude that the Z11 was factored up to FHP=480 at least, bumping it up to S/S at W/P=3341/480=6.96, then making the car illegal for 1965-66-67 as too light. Sorry for so much verbiage but some of these mysteries are in the math.

I’m gonna go with “IF Z11 LEGAL THEN FACTORED TO A LOFTY AND UNFAIR FHP=480” for now as the saga continues.

More pictures and comments on this conundrum are welcome if anybody remembers!

 

This one didnt sell June 2023 BAT, high bid $298000.
Mainly tho look at the pics, story, AMA specs in there, 3345 shipping weight & hand written 7.77 for W/P

https://bringatrailer.com/listing/1963-chevrolet-impala-z11/

 

the Z-11 had the same issue as the ZL-1 Camaro did, which was pretty much the replacement to the Z-11 with the 5 year rule as it also broke that 8lb rule as well.

 

I saw one at Drag Fest a few years ago. Can't remember the owner's name, maybe Denzel? Does anyone know the weight of these light weights with all the aluminum and fiberglass?

 

See my post #26 above, NHRA lists the shipping weight at 3341 lb

The handwriting on the AMA sheet in Post #27 looks like that car weighed 3400 but not sure how much gas was in it.