what do yall think about this 95

[FastOrange]

You must be registered for see images attach

that explain abit better?

EDIT: this one is missing solenoid though.

 

[radical7]

Yeah I think most, if not all white trucks got blue interiors.

not really there were a lot that were red/maroon or tan

 

[sewlow]

Yep! There's a low pressure area in the front of the windshield, close to the bottom, at the back of the hood. GM engineers found this & utilized it to draw fresh air into the carb.

 

[Tempted]

The DZ302 used a very high rise intake that did not fit under the stock SS hood. This is why the Z28 got the cowl. It is also why the air cleaner is so short. Most Z28 owners went with a standard open element breather back when the cars were new but when the prices went through the roof, they started finding original intakes and putting them back on the cars for the "all original" sale. Drawing in air from behind a hood where there is a lower pressure due to aerodynamics is not an efficient way to "upgrade" the intake. Higher pressure means it is easier to draw in air. Lower pressure is like driving in Colorado.

 

[FastOrange]

The DZ302 used a very high rise intake that did not fit under the stock SS hood. This is why the Z28 got the cowl. It is also why the air cleaner is so short. Most Z28 owners went with a standard open element breather back when the cars were new but when the prices went through the roof, they started finding original intakes and putting them back on the cars for the "all original" sale. Drawing in air from behind a hood where there is a lower pressure due to aerodynamics is not an efficient way to "upgrade" the intake. Higher pressure means it is easier to draw in air. Lower pressure is like driving in Colorado.

not true at all, they cowl hood was NOT designed just for the Z28, it was designed to draw in air from cowl area. also, the z28 "High rise" intake is not a "Very" high rise intake, basically the same as a Edelbrock Performer RPM. which fits under a stock hood no problem

 

[The Fiddle]

The DZ302 used a very high rise intake that did not fit under the stock SS hood. This is why the Z28 got the cowl. It is also why the air cleaner is so short. Most Z28 owners went with a standard open element breather back when the cars were new but when the prices went through the roof, they started finding original intakes and putting them back on the cars for the "all original" sale. Drawing in air from behind a hood where there is a lower pressure due to aerodynamics is not an efficient way to "upgrade" the intake. Higher pressure means it is easier to draw in air. Lower pressure is like driving in Colorado.

Let me tell you about driving in Colorado...

 

[FastOrange]

BTW, some info

Only 602 Z/28s were sold in 1967, along with approximately 100 Indianapolis Pace Car replicas.[3] The 1967 and 1968 Z/28s did not have the cowl induction hood, optional on the 1969 Z/28s. The 1967 Z28 received air from an open element air cleaner or from an optional cowl plenum duct attached to the side of the air cleaner that ran to the firewall and got air from the cowl vents. 15-inch rally wheels were included with Z/28s had while all other 1967-9 Camaros had 14-inch wheels.

 

[sewlow]

My bad. Meant high pressure. (Need more coffee!)

1969 CAMARO "SUPER SCOOP"

RPO ZL2 - SPECIAL DUCTED HOOD: RACE-BRED TECHNOLOGY
by Wayne D. Guinn An insider's look at the development of the Cowl Induction hood by the author of
"Camaro - Untold Secrets"

​

The hood dubbed "Super Scoop" by Chevrolet was designed specifically to be a functional piece of high-performance equipment. The intention was to increase overall horsepower by delivering cold fresh air to the induction system. Not only did it effectively accomplish its primary objective, but its stylistic beauty greatly contributed to the mark resulting in the classic appearance of the 1969 Camaro equipped with the "Cowl Induction" hood.
THE COLD AIR THEORY

The principle of utilizing cold air induction was nothing new at Chevrolet. It was used in racing as far back as 1963 on the Chevrolet Z11 stock cars running on the NASCAR circuit and again with the "Plenum Air Intake" released as a special service option for the race-oriented 1968 Z/28s. Rather than using a raised hood panel like the 1969 RPO ZL2 option, the first two designs drafted cold air from the base of the windshield under the hood via a special air cleaner and duct, much like the NASCAR racers of today.

Chevy engineer Doug Roe, who worked with Product Promotions chief Vince Piggins, found a dramatic performance gain by taking the cool dense air at the high pressure area near the base of the windshield. Ducting pressurized fresh cold air from this area to the carburetor creates a more dense fuel charge with increased volumetric efficiency resulting in more horsepower An approximate 1% horsepower increase is gained for every 11 degree drop in temperature providing the mixture is adjusted accordingly. That means if your engine has a gross horsepower rating of 350, a drop of 43 degrees would net you an additional horsepower increase of 4%, equal to 14 hp, for a total of 364 hp. These gains are typical, since under hood temperatures in normal conditions are relatively hot, and under racing conditional even hotter. Therefore, given the temperature differential of under hood and outside the hood along with pressurized unrestricted air flow, it is not unreasonable to expect this type of power gain at the upper levels of engine performance.

Small block cars, like this 350-powered Pace Car, used an additional spacer ring between the air cleaner housing and the seal for proper air cleaner assembly height.

​

The reverse drafting method used on the special ZL2 hood was chosen over forward facing scoops which create greater pressures and increased ram effect but have problems associated with air turbulence at the carburetor air horn. Turbulence causes uneven pressures within the metering bodies and upsets correct air/fuel ratio and delivery. Correcting this type of system is involved and not worth the insignificant power increase the additional pressure affords.


DEVELOPMENT

Larry Shinoda, of Chevrolet's design group, began development of the hood system approximately May 1967. That primary aim of the system was to give advantage to the TRANS-AM competing Camaro Z/28s. Although the hood was fully developed and ready much earlier, the concept reached the production level for the 1969 model year.
The delay can be indirectly attributed to the SPORTS CAR CLUB of AMERICA (SCCA). Chevrolet held back the special hood production until it could be homologated into the SCCA TRANS-AM events. It wasn't until the 1969 racing season that the SCCA loosened up and allowed hood scoops, stipulating that they must be of "modest" design and in no way interfere with driver vision.

The 1969 SCCA recognition forms filed by Chevrolet included the RPO ZL2 single four barrel "steel hood" in order to satisfy the minimum production number of 1,000 units necessary to utilize these parts in the racing series. Chevrolet then qualified the rare counter part fiberglass 2x4 hood as optional heavy-duty equipment for use in the series. It was strictly a matter of economics that led Chevrolet to produce and homologate the steel hood even though it was their intention to use the fiberglass hood in the racing series.

Chevy used the fiberglass hood (on the left) for the actual Trans-Am competition cars in '69, but nothing stopped a Camaro owner from purchasing the hood over-the-counter at the local Chevy dealer. Note how the 'glass hood's air cleaner opening is set up to fit the four-barrel crossram air cleaner.

​

As you can see, the folks at Chevrolet were masters at SCCA rule bending and/or interpretation -especially when it came to economics and gaining advantage in competition. Consequently, an extremely LIMITED production of fiberglass hoods were sold in stark contrast to the unlimited production run of 1969 RPO ZL2 "Special Ducted Hoods", which sold an amazing 10,026 units due to their overwhelming popularity. There is no doubt that the TRANS-AM race car's appearance with the hood had an impact on the buyer.

The fiberglass hood was costly to produce. If the SCCA were to hold Chevrolet to the 1,000-unit minimum production number and sales for the fiberglass hood were realistically targeted at a mere 100 units, the expense of production would be justification alone nor to produce the fiberglass hood. However since the steel counterpart was inexpensive to produce (relative to the fiberglass unit) the steel units would be easier to justify cost-wise as a Regular Production Option (RPO) with a sales potential of well over 1000 units. Because the steel hood and the fiberglass were of the same basic design and function, it would be easy to homologate the steel hood on the recognition form, and then offer the fiberglass hood as a "heavy-duty" service option allowing Chevrolet to produce only as many fiberglass hoods as they determined there was a need for.

FUNCTIONAL DESIGN

The RPO ZL2 system works by drafting air through the special ducted hood from an opening near the base of the windshield. The rear facing air intake is well-shrouded in an effort to smooth out excessive turbulence. An air valve is placed at the opening which is controlled by an electric solenoid and activated by a switch on the throttle arm. The valve opens when the throttle is approximately 90% depressed. With the valve open, cold air is directed though the hood's raised plenum chamber to a special air filter that seals to the hood and delivers the cold air to the carburetor.

WHY AN AIR VALVE?

The air valve was specified fur use on the production RPO ZL2 option for the sake of better overall drivability. Taking into account the diversity of climatic conditions and their effects on the system, it was determined that the system should function only when called on. If the system remains open in extreme cold weather, icing of the carburetor could occur. The valve also affords longer air filter service life.

Due to the taller engine height, the air cleaner assembly installed on big-block Camaros required no spacer. The air cleaner baseplate fit both Quadrajet and Holley carburetors.

The smallish, single snorkle exiting the passenger side of the air cleaner provided underhood air to the carburetor during normal driving. When the throttle was opened fully (over 90%) fresh, cold air from the cowl area flooded the air cleaner assembly. The shape of the air cleaner seal allowed the rubber to "collapse" when the hood was closed. This ensured a positive seal against the underside of the hood.

​

AVAILABILITY

RPO ZL2 was available on Z/28, SS350 and 396 models, each of which uses a slightly different setup. The main difference lies in the height of the extension ring used on the air cleaner. The extension ring fills the gap between the carburetor and hood, the exception being the 396 model where no extension ring is used. The Z/28 package included a 302 ernblem on the hood, whereas the SS cars used no additional emblems. The optional equipment price when ordering RPO ZL2 in 1969 was $79.00.

​

The cowl induction hood was and still is one of the most popular options offered for the first generation Camaro. The combination of its aggressive good looks and ability to lend additional power without engine alterations is truly amazing. Best of all is the sen sation derived by pressing your foot down, hearing the flap open with a unique roar of air rushing in and the whining gearbox in concert with that free-flowing tune of extra horsepower!

RPO ZL2, form and function . ..

This article originally appeared in the Spring 1996 Issue of YEAR ONE's Restoration Review magazine. Restoration Review is intended as a forum for and about the vintage automobile restoration hobby. For more information about Restoration Review or to subscribe please call YEAR ONE today ! 1-800-950-9503​

 

[Tempted]

And the Tornado intake blockage was "proven" to make more power and better mileage as well.

As far as the DZ302, it wasn't available in 67 or 68, it was a 69 only motor.

 

[sewlow]

All had a 302 cubic inch engine with a suffix code MO or MP in '67, MI or MO in '68 and DZ in '69. To get the 302 engine Chevy took a 283 crank and put it in a 327 block. Some people say Chevy put the crank in a 350 block but since 1967 was the first year for 350's and 302's and both used the 327 block it is better to say they used a 327 block. A 302, 327 and 350 block are exactly the same except for the number of main bolts which would depend on the application and the year. The 1969 302's had 4 bolt mains. The 1967 and 1968 302's did not have 4 bolt mains. They were in fact 2 bolt main blocks used in '67 and '68 302's. In 1967 they are small journal blocks and in '68 and '69 they went to large journals. The reason for the Z28 was to compete in SCCA Trans-Am Challenge Series. The engine requirements to race in SCCA was limited to 305 cubic inches. All had 4 speed Muncie manual transmissions. All had power front disc brakes at least. All had 12 bolt rear ends but didn't have to be posi. None had A/C. None were factory convertibles except one beautiful '68 Z28 was a convertible which was made for the head of Chevrolet at the time (Pete Estes) and if you own it email us a picture and all the info you can please! Just remember badges do not a Camaro Z28 make. There is NO code in the VIN that recognizes a Z28 in any first generation Camaros. Late '69 Camaros had an "X" code on the trim tag though. A Protect-o-plate can be helpful in identifying a first gen

Option​	Required for a Z28​	Available on base Camaros​	Easily Purchased and Added​
Special Engine	Yes (see above)	No	NO! Very hard to fake especially the casting number and casting date
Z28 Emblems	Yes (some were "302" and some were "Z28")	No	Very much YES!
Stripes	Yes	No	Yes!
Special Hood	Not all but most	No	Yes!
Front disc brakes	Yes (Brakes could NOT be front drum brakes)	Yes - but most got drum brakes.	Yes! Check that they are not after market though.
Special Instruments - Amp, temp, oil pressure, fuel, clock, tach	No - that's right NO not required.	Yes - just required V8 and Console	Yes! They were AC gauges. Also tach's were dealer installed or factory late in 69.
12 bolt rear end	Yes but didn't have to be a posi	Yes - but check dates of rear end	Not easy to find one dated for a specific Camaro build date.
Automatic (ANY)	NO! Automatic was not available on any first gen Z28	Yes	Easy to change to 4 speed but not easy to fake correct 4 speed trans with partial VIN. Also be sure to check manual transmission. The Z28 Trans was not a Saginaw it was a Muncie. Saginaw was the "low" performance manual trans.
"X33" or "X77" Code on trim tag on 1969's only	Yes but for late style Norwood assembled '69 Camaros only! [SIZE=-2](No so called "X" codes on Van Nuys assembled Camaros)[/SIZE]	No - Base Camaros got "X11"	Not easily added but check VIN to make sure it was a V8 because trim tags are getting swapped out. Also have seen people selling reproduced trim tags so watch out.