mako1969

Before going any further, let me clearly state: I AM NOT TRYING TO START A FLAME WAR. The following is a posting of DOCUMENTED FACTS.

Seems that there has been quite a lot of discussion as to the performance of a stock L88 Corvette or ZL1 Camaro. Year One sponsors a drag racing event called FAST (Factory Appearing Stock Tire) and also an F/S (Factory Stock) category. There are also the PSMCDR or Pure Stock Muscle Car Drag Race events.

For those who are wondering, here are the rules for the Factory Stock category involving an L88 or a ZL1:

Basic Rules Of The Factory Stock Class

Clones of limited available cars:
If you have a 68/69 427 COPO car clone.
If you have an L88 / ZL1 Corvette.

You must have an EXACT match clone.

You may run the Aluminum heads on your EXACT match clone only if they are the EXACT year, and EXACT OEM casting number for your engine & car.

In General:
Clones are OK, but they must be EXACT correct.

http://forums.factorystockmusclecars...71/m/626107086

Note that is states EXACT. Not "close", "in the spirit of", etc., but EXACT. These cars are subjected to engine tear down and verification of CID, CR's, cam size, carb size, etc. In short, those that run these events are experts in the field with sophisticated test equipment, they don't play around, and cheaters are disqualified.

All cars must run the full OEM factory exhaust system including manifolds (no "trunk option" headers allowed), pipes, and mufflers. They must also run on correct (size, full tread) reproduction BIAS PLY tires as were stock on the car.

The fastest times recorded in Factory Stock are as follows:

Jim Johnston 1969 ZL1 427 Corvette 11.58 @ 121 F/S 11-12-05 Raceway Park, Englishtown, NJ

Peter Simpson 1969 ZL1 427 Camaro 11.75 @ 117 F/S 11-12-05 Raceway Park, Englishtown, NJ

http://forums.factorystockmusclecars...81/m/309106276

Jimmy Johnston 1969 L88 Corvette 11.71 @ 121 F/S 10-08-04 Atlanta Dragway, Commerce, Georgia

Wayne Nelson 1969 L88 Corvette 11.74 @ 119 F/S 05-07-04 US 41 Dragway in Morocco, Indiana

http://www.geocities.com/fadrags4/

Now I have also seen a post in which the owner of a C6Z06 issued a challenge to race a stock L88. Car and Driver magazine recorded 11.7 seconds @ 125 mph in their test of a C6Z06.

Who knows? One of the automotive publications might love to do a feature on one of the above Factory Stock entrants versus a modern Z06 in a 1/4 mile race.

Yes, the C6Z06 is light years ahead of 1969 technology, and lap times around any race course would be far superior to anything stock from 1969, but a 1/4 mile drag race would be quite interesting to say the least!

sxr6

Thanks for the read...

Still say if your compairing the new vs old it doesn't seem fair to hamper the old girl with tires G70x15 in most cases

Mid 11s with those tires certainly make 10s attainable with any good chunk of rubber on the back

mrvette

OH GAWD YES!!!! Tire tech is the single largest improvement in the last 40 years....jeez even my silly 17 inch '92 vette wheels and 275 rubber are better than anyting similar to stock any shark ever saw....

GENE

Maymyvetteliveforevr

Thanks for the info, interesting!

GrandSportC3

11.58 @ 121 is pretty impressive on those tires...

On Mickey thompson ET Street Drag Radials, The ZL1 would for sure run 10's!!

If both, C6 Z06 and ZL1 would run on slicks, the ZL1 would win without a doubt!!

Rowdy Rat

FAST is not really geared towards "stock"... As the acronym states, it is factory appearing which means that while the external engine parts look like the orignal parts, the racers are free to change internal parts that are not seen. Most of the engines are running much more displacement and compression than the original applications that they claim to be.

The PSMCDR is interesting and personally, it is an event that I will definitely try at some point. That being said, the engine specs that are allowed (even those allowed in the certified stock classification where the engine is partially torn down) are more in line with NHRA specs which are much more aggressive than the published factory specs.

Then there is the issue with the cars themselves. While the intent is to allow exact "tribute cars" (aka "clones") to run, there may be a tendency to take liberties while building the car such as leaving non-visible parts off, not putting all the undercoating back, keeping the the paint to a minimum... Anything to keep the car light. The question that I have is, "If you took these cars to a judged event (say an NCRS event iin the case of Corvettes), how would they fare?"

For those who are wondering, here are the rules for the Factory Stock category involving an L88 or a ZL1:

As noted above, the spirit of the event is to have stock cars exactly identical to how they appeared back in the 1960s and 1970s, but that isn't always the case in execution. The engine specs can be taken to NHRA stock class limits which isn't factory stock at all and the issue with building a perfect tribute car was addressed above.

Yes, they have to be correct castings, but that's where the rules start to stray from stock. Three angle valve jobs? The factory never provided them back in the day, but the rules allow you to do it. Mill heads to reduce combustion chamber volume to NHRA stock specs? The rules allow this even though the factory specs were always on the high side of their nominal publised ratings. Equalize combustion chamber volume? Factory never did it, but the rules allow it. Stock camshaft? The rules allow for a cam with stock lift and duration, but you're free to play with the everything in between. Stock valves? While they can't be undercut you can use any valve you want... Same goes for valve springs.

These cars are NOT exact copies of their stock counterparts.

Blatant abuse of the rules is not tolerated, but as mentioned above, these cars are NOT exactly like their stock counterparts. They look pretty darn close, but they have been massaged to varying degrees.

All cars are allowed to run up to a 2½" diameter exhaust... Even if the factory never offered it. How does that rule sit with a 1969 L-88 Corvette that was delivered from the factory ("stock") with a 2" exhaust? That's not exact in anyones definition.

For the record, Corvettes of the late 1960s/early 1970s were delivered with nylon belted tires, not bias ply.

Considering that these cars are running on F70-15 tires, the times are incredible for cars approching forty years old. The same caveat applies though... These cars are not exact copies. Some are closer than others, but they are not exact.

A forum member already clocked 11.2s @ 127 with his stock 2006 Z06 on the stock tires. It's still the faster car. If you want to compare magazine articles, I guarantee that we can find some 13 second L-88 quarter mile times.

Personally, I love the styling of the old cars and the L-88 is a true racing legend in its own right. While one of the current "tribute cars" in PSMCDR trim might make a good showing at the drag strip, the new Z06 will clean house in any objective performance tests that you could possibly think of.

The L-88 was a great car in its day (and is still one of the most historically significant vehicles GM ever built). The 2006 Z06 is better.

Regards,

GrandSportC3

I'd bet that a ZL-1 Vette to original specs with slicks, 4.56 gears (avalable option in '69) and a experienced driver will beat a C6 Z06 on slicks with an experienced driver..

Just take a look at the specs:

C6 Z06: 500 HP, 3150 lbs
'69 ZL1: 580 HP (and a lot more torque), 3250 lbs (approx.)

The ZL1 is a approx. 10.80 car with that setup and a good driver..

However, the question is if the ZL1's differential/axles/half shafts will stay in one piece if launching at 6 grand and power shifting at 7500 RPM

doug_dayson

Back in 1969, Gib Hufstader, Tom Langdon, and some other GM Powertrain folks blueprinted a 69 ZL1 with stock components excepting Carb, Slicks, and Headers.

The Stock Heads were mildly cleaned up (deburred but not enlarged, and cc'd to minimum spec for a CR of 11.5, valve job), a Holley 4500 and 3/4" Spacer were used on the gasket matched Stock Manifold, Stock Cam, 4.88 Gears with 10.5" Slicks (including a 2" Block on top of the Hub Carrier to eliminate wheel hop), and a TH-400 with Shift Kit and a 2800 Stall Converter.

This ZL1 weighed in at 3000lbs wet (w/o driver).

Best time was 10.60 @ 132 MPH!

This was done with a 6K RPM neutral dump!

The new Z06 could be ballpark with similar mods, but I doubt it could match this due to it's weight?

This article is from the Oct 69 Motor Trend...

Doug

PRNDL

Those FAST cars and the "Factory Stock" cars are incredibly cool but they really aren't the same as a showroom stock car of the day. With my sharp NCRS-trained eyes ( <== ) I noticed the mandrel-bent 2.5" exhaust under the Factory Stock L-88. Probably a total deduction at the NCRS meet, but we will have to get the team leader to sign off on that.

you can almost see it here=>


The part I still don't understand is the tires. These guys are getting incredible 60 ft times, well under 2 secs, with these 15" F70 bias ply repros. I don't know if they are bias ply tires, or radial reproductions of bias ply tires. At the FAST race a nonauthoritative source (this was a guy in a bracket class, not one of the FS racers) told me that the tires could be special ordered from Coker made with a modern rubber compound, sticky and similar to drag radials. But one of the FAST class racers assured me they were just the regular repro tires purchased from Coker, and the great 60 ft times were achieved with launch technique and glue.

So, that remains the mystery to me. I see the exhaust is better than factory. I know they can massage the engine internals. I still have no idea how they get those tires to hook!


here is a better view:

Glensgages

..... sure like to know how-well some of these 'FAST' cars 60'.....

mako1969

To answer some of the questions, the Factory Stock events do have some leeway, except for the L88/ZL1's. No internal modifications are allowed to the exhaust system, and they also state "We are not going by NHRA rules" so cylinder chamber modification to bump compression is not allowed. The psmcdr events are far more stringent, Pete Simpson and Jim Johnston compete in both, and to the best of my knowledge they are not swapping out engines/parts per event. Soft compound "repro" tires are not allowed.

http://www.geocities.com/psmcdr/rules.html

Pete Simpson's Camaro has been "certified stock" including engine displacement, bore, cam specs, exhaust, etc. His camshaft is a GM NOS ZL1 part. According to an article on the car in the March 2006 issue of Drag Racer magazine, the only modification to the motor is a PerTronix modification to the stock ignition. The article does not mention what this is, but from what I have seen in testing over the years, most of these mods are worth less than 10 hp.

http://www.yenko.net/ubbthreads/show.../page/0#193421

As for blueprinting the motor and "stock" configuration, here is a quote from the December 2000 issue of Auto Restorer magazine:

"Five employees were trained in ZL1 assembly and worked in a clean room putting the engines together. All engines were blueprinted to spec and balanced. It took almost 16 hours for the specially trained team to assemble each engine."

Therefore, a balanced/blueprinted ZL1 motor IS stock.

Also, IIRC 2 1/2" exhaust pipes were stock on BBC motors in 1969.

Rowdy Rat

[QUOTE=mako1969]To answer some of the questions, the Factory Stock events do have some leeway...[quote]

They have a lot of leeway. I've talked to Dan Jensen regarding running a 1970 ZR-1 tribute car at his event. The rules leave a LOT of room to play around with the car if you know what you are doing. A car staying within the rules, but "pushing the envelope" as far as the rules will allow will net you a car that is much quicker than anything the factory ever built... That's a fact.

While the PSMCDR rules may have changed with the last year (the last time I inquired about running in this event), L-88s were held to the same rules that all of the other cars were held to... Which means that they were open to the same interpretation of the rules as well. If I remember correctly, ZL-1 Camaros were legal to run, but ZL-1 Corvettes were not due to the low production number. That restriction may have changed, but I haven't heard anything about it yet.

Which is absolutely not true. While I'm sure that the organizers wish you to run a "stock" exhaust system, the rules allow otherwise. Take a look at the photo of JJ's Corvette that MJ posted above. That is NOT a stock exhaust system... For any year Corvette.

The rules have always allowed milling the heads to NHRA legal specs... Along with all of the other changes that I mentioned in my previos post per my conversation with Dan Jensen a year ago. I don't believe that anything has changed since that time since it would affect those cars already competing in the "certified stock" part of the program.

Yes, they are competing in both events... I don't know what they are running from race to race. Pete posts over on the Supercar Forum... Most of what he says that he runs is pretty stock, but don't think for a moment that he doesn't have a few tricks built into that car.

This is true and to my understanding, the rubber is check if there is a question as to whether it is "stock" or not. Personally, I'm of the same opinion as MJ... I'm in awe that these guys are turning high 1.7 - low 1.8 60' times. Absolutely incredible.

That's the starting point, but as noted above, my discussion with one of the organizers of this event made it clear that the car could be built to be a lot quicker than "stock" and still be considered as such.

That engine is not pushed to the limit of NHRA specs at all from what Pete has mentioned, but as I said before, he certainly has a few tricks up his sleeve in addition to the Pertronix ignition... Better believe it.

All ZL-1 engines were built in a temperature controlled environment which would require them to be built in a special "area" at Tonawanda. ALL Chevrolet engines were "hand assembled" with "balanced assemblies" from the engine assembly plants... That's just how it was done. Parts within a certain spec range were grouped together and then used in an engine within a certain tolerance range. This was done more to reduce warranty issues than anything and not to improve performance. This was NOT the type of balancing and blueprinting that goes into a high performance or race engine today.

To say that ZL-1s were balanced and blueprinted is misleading because they were not to the level of precision that people today associate with those terms. John Z who posts on these boards was involved with the ZL-1 Camaro program at Norwood, OH... Might not have much knowledge of the assembly process at Tonawanda, NY, but he might add his expertise to the mix.

No they weren't... Take it from a guy who has researched 1968-1972 exhaust systems for years and has seen his fair share of original Corvette systems. ALL Corvettes delivered in 1969 used a 2" exhaust system... Big block or small block makes no difference. In 1968 and again in 1970-1972, big blocks used a 2½" exhaust system (along with LT-1s), but not in 1969.

The cars that are racing in the PSMCDR are impressive performers, but they are not "bone stock"... That's a fact.

Regards,

Stan Falenski

VetteLS6

Bone Stock??????? What is that.....lol......It is very easy to believe that with modern tires one could clip well into the tens (10s) with one of these cars......\
My Friend Don who raced with Jenkins back in the heyday of the Camaros held the NHRA Record for my years in Super Stock with his Busted Budget 302/69....that baby clocked a 10.78 at well over 120mph. Yes it was stock parts! Now lets qualify this....Factory Heads, factory crank, Factory Trans, Factory rear....It did have lights and windows with full seats and dash......hmmmm
The lights were there but the internals were removed, Rear AKA 59 Pontiac...stuffed with 5.89 gears or even 6.14 gears depending on the conditions.....Tires....hmmm lets just say huge.....no tubs though. Transmission was a very worked over PG with a hand made sump for cooling, back in the day you had to do this good stuff by hand.....oh yeah the record was with a stick (M22)....what was I thinking. TI ignition was used. No wiring harness in the car other than the bare minimum. The windows are real....just they dont go down (internals removed).....hey come to think of it...the front wheel studs are hand made aluminum hollow! It even has a radio!....or should I say radio face....no guts. OK OK you get the idea.....What did the 60' look like.....like hell was going to come home....7800 rpm launch....up shifts at better than 9000....or when the mouse went over the hill.....wow 290hp??????....NHRA re-factored it @415hp...more like 500HP...on a single factory....lol 4bbl?....yeah the dual quads didnt work as good the worked 800 Holley. The car still lives today it has only 8000 miles on it....lmao 1/4mi at a time.....Yes I think a L88/ZL1 would stomp a Z06.
Back in 1990 I was over Don's house and had the opportunity to drive Busted Budget on 60/84 heading towards Cannon AFB, NM....It was pure animal. From my opinion it could walk all over my BB Vette all day long.....very consistant in launch and tracking. Lets just say Traction wasn't the issue it was more a issue of nerve with the Super Minimouse under the hood. This would blow the doors off any Z06 car and yet it was a small block single 4bbl. Factory Super Stock!

Super Stock -- Kenny Schindler, Corvette, 9.268, 142.85 def. Ronnie
Courtney, Cavalier, 9.849, 127.24.

Some Specs of another Z28
TECHNICAL DATA
VIN number 124378N411100
Build Date 04A (first week of April)
Color Corvette Bronze
Interior Code 712, black standard
Car Shipper Shipped on April 11, 1968 to Ammon R. Smith Auto Company, York, PA
Engine Data Cubic Inches, 302
Cylinder heads #3917291, completely stock, no porting allowed!
Stock rocker arms & valve springs
Intake 302 aluminum intake, casting #3917610
Carburetor Holley, #4053, 780 CFM 4bbl
Camshaft Crane, .480 inches lift, 272 degrees duration, valve lash, .016-.016
Pistons GM 302, .030" oversize
Horsepower 456 @7700rpm
Rear Tires 9" x 30.0" Hoosier's
Rear axle & ratio 12-bolt, 5.57 Richmond Pro Gears
Clutch 10 inch, three finger from Advance Clutch Technology
Shift Points 8200 RPM
BEST ET 10.80 @122.30mph


Just a opinion,
Larry

ajrothm

Bumping this old thread up because today I found the Oct 69 Motor Trend that Doug posted about 3 yrs ago. I just bought it. I look forward to reading the original article about modding the ZL1 for strip action. I will scan the article and post it up here for those interested....Just something I came across and thought it was neat.

Gale Banks 80'

A couple things come to mind first of all that it took some 39 Years for a Corvette to be as quik in the 1/4 again even with the tech that has jumped leaps and bounds. And after all these years the 426 Hemi Mopar guys are still pissed that hey arn't at the top.

63mako

Sorry to pop the OP's bubble but these cars Bone Stock were running 13's. Dick Harrell was in the 10's but there were a lot of changes made to get there. The FAST class cars are not even close to what came off the showroom floor. These Factory appearing engines are at least $30,000 to build to be competative. Decked blocks and heads, Overbore is allowed, Specially designed cams, CC'ed heads, They might flow 20 different heads to get the very best flowing head that is the right part number. Hot honing. Low pressure rings, larger clearances to reduce friction. Flow testing different valve grinds, manufacturers and designed valves. Everythink on these is optimised to pull every last HP out of them.
Here is a dyno test of Pete Simpsons ZL1.
http://members.***.net/harddrivin1le/ZL1DYNOTEST.JPG

LS4 PILOT

Ruttttt.ro..... sounds like a declaration of war ..........HEE HEE HEE

subscribed

morganjd

I race in the pure stock muscle car races and also the FAST races here in michigan, let me clear up a few points and give everybody here the real facts. 63mako is correct on the FAST cars, they must appear stock and sound somewhat stock (they never sound stock)You can do anything internally to the motor, solid rollers, extrude honed exhaust manifolds, wilson manifolds cuts the intakes in half, reworks them and then welds them back together (cost $3,000-$4,000), they lighten the cars and go as far as removing every other seat spring to reduce weight, electric fuel pumps in the gas tank that has been divided in half and contains the real battery, the one in the engine comartment is an empty case. They even make the front license plate bracket out of alluminum to save a pound. The l88 orange vette that scott pennigton runs in fast is a 500 inch, 16 to 1 compression L88 clone. The tires are STOCK REPRO bias ply goodyear in f70, or g70 firestone wide ovals, word is the firestones are softer, and hence used by most of the racers. How do we get them too hook up, run 40lbs of air in the rear and 45-50 in the front. You keep adding air pressure and doing test burn outs untill the patch is even accross the entire width. You would be surprised how soft the compound is and how good they really do hook up. The fast cars are really purpose built race cars that look stock, btw, they shave the tires down so that they have little or no tread and appear to look like slicks. Most of the fast cars and for that fact most of the pure stock cars are AUTOMATICS. They have gotten down to the low 10's at over 130mph in FAST

PURE STOCK - they do allow the motor to be NHRA blue printed, for example my 71 LS6 came with 9 to 1, they allow me to go to 11 to 1, hence i just did it after the fall race, the other LS6 car goes 11.90's. You must run the stock heads, intake, block, carb (no double pumpers if the car came with a vacumm holley). You can run a 2 1/2 inch exhaust with either an H or X pipe, mandrel is ok, mufflers must be stock appearing and crimped, no flowmasters, dyno max ultra flow is the choice of the vettes, side pipes will kill cost you 3 tenths. You must run the stock transmission, any gear, they run wide ratio muncies and 4.56 gears. The cam must be stock specs, and they say that the crane blue print cam is the best out there. Roller tips are legal, full rollers are not. They loosen the front sway bar, no drag shocks, look at the way the launch. The trick is to use worn out front shocks to get the weight transfer. If a car runs 11.99 or faster, they want to inspect it and then they pump it for stock bore .090 over is max and compression, check spring pressure, No roller cams allowed and put a bore camera down the carb to look for undercut valves and dome pistons (if car had flat tops, it must still have flat tops), no head porting of any kind is allowed, no gasket matching either. The most impressive car to run is JJ's silver L88, as it is a 4 speed and he can shift it like no body else out there, all of the other quick 8 cars are automatics. 3 of the 4 top cars are l88's, with the other one being my buddy Bob K's hemi cuda, no one has run a ZL1 vette as of yet, but dan Jenson told me he would not have a problem allowing one to race. In my opinion, it better be either white or yellow and have the stripe.The top racers in pure stock spend alot of time and money to get these things to run, the others just have the most fun you can have with your clothes on, great group of guys, they hang out on the V8 buick board under the pure stocker boards

Solid LT1

I think on slicks it would SCATTER the IRS unit all over the track but, what do I know?

Ironcross

NHRA`s Mopar Hemi shootout with 1968 Cudas run 8.6-8.7`s at a buck fifty plus and are stock...What stock or otherwise C-6 can top that....Hemi`s do rule...all the rest follow in there pecking order....