Correct Manifold for Comp Cars with Hi Rise Heads?

[Michael4yah]

CW can you post the 4bbl manifold in my gallery. Im a technologically handicapped!!!

[computerworks]

It's not so tough...

When you view the pic in your Gallery...just below it is a string called UBBCode.

Just highlight the whole string, point to it and right-click-COPY.

Then, start your new post and, at the point you want your picture to appear... just right-click-PASTE

[Byots]

nm .

[Cobra #3170]

Do you know what specific races Essex Wire ran Webbers and in what class did it compete? The point here is that if the car ran an unlimited class it could run Webbers if it ran A production it could not, under SCCA rules. Mr. Ford still had an Italian made wife at the time I wonder how she felt about the no Italian parts edict.
I know that they explored both Webbers and mechanical injection on the CanAm
effort but have still not heard of a specific race location and date where a Webber 427 Cobra ran. The reason for my curiosity is that I asked Shelby American that very question in 1966 and was told that it wasn't necessary because the 427 had adequate power with the single four.

[Excaliber]

Seems to me the data I've seen suggests the Holley carb makes more horse power at the upper end of the rpm band than the Webers. But the Webers did better at low and mid range rpm. Single four produced 'enough hp'? An effective way to dismiss the Webers question if you ask me. Shelby went to 2X4 intake for Le Mans in an effort to increase hp over a single four! On THAT track, with it's demand for max hp I could see not using the Webers.

Dry sump because of reliability issues and not required on the small blocks? Balderdash I say! If your looking for max hp it's logical to go dry sump, and the small blocks would have benefited to that end as well.

That motor in CSX3002 (the Turd?) pictured above was the first 'experimental' all alloy 390 side oiler.

[Michael4yah]

Ernie, Hows it. It would depend on the course. At Le Mans they have that long straight called "The Mulsanne that can make you or break you time wise. The fastest car on that part of the course had a distinct advantage and was usually a front runner or winner. If your talking 48s then a 4bbl seems to be the way to go. But many road courses the Webers have an edge. Their throttle response and torque gives them an edge especially in passing. Thats why Ken Miles begged for them to be put on his car. Here ya go Ernie, wanna see what the Mulsanne Straight looks like in a Porsche 956 doing 246 mph down the straight?
http://www.youtube.com/watch?v=iQbmv12s-Yk&NR=1
Enjoy, Michael

[Excaliber]

I agree, throttle response would be a significant factor on the shorter courses, hence the desirability of Webers in such a case. No question Shelby was seeking max mph and thus hp for Le Mans. I think the target speed that MUST be achieved in 1965 or so was around 185 mph minimum. Two chicanes have been added to Le Mans in recent years to lower max mph on that long straight!

Hmmmm, I wonder what the Cobra drag race cars (289-427) preferred for the best time? No doubt they used a variety of intakes in the search for optimum performance.

[Michael4yah]

Ernie, did you watch the Le Mans video? Man that guy was flying. The trees really bring it all into perspective. I just bought that single 4bbl manifold in the photo near the top of the page. I think Im going to put my Tunnel Wedge Hi Riser intake and carbs up for sale. Havnt made up my mind completely. I may use it to rig some webers. You cant find a Hi Rise Weber manifold to save your life! Yup that Mulsanne Straight Changed the Cobra forever. The little sports car body was no match for the streamline bodies of the Gt 40 and the Daytona Coupe. I wonder how fast they had the Daytona Coupe going on that straight. I'll bet it was near 200. After watching that video I cant imagine going that fast on that course in a Cobra!! Yikes.

[Byots]

nm .

[Cobra #3170]

Originally Posted by Byots

You would need a modern worked/ported spider intake with max prepped dominator carb to match the top end power of the webers, and your low speed performance would then be terrible - and it wouldn't be period correct/original. Hofstaedter dyno tested all the factory HR inductions and the 58mm webers made notably more power at every engine speed, including in excess of 7,000 rpm. Dyno testing back in 1964 at SA showed the 58's to make significantly more top end power than the 1x4. It is a widely known fact that webers in general will give you significantly better mid range power, one reason why in a road race the webers give lowest lap times and why SA used them on all the factory race cars. F1 used webers and even today still use IR in what is essentially the evolution of webers, fuel injection. If the most sophisticated race series in the world uses IR, it must have some ideal attributes.

Bottom line, the 58mm webers were the top of the line available option from SA for the big block Cobras back in the day and was planned on being used on team race cars, especially at Lemans, had there been a factory effort (the big block configured coupe was even sent to Lemans in '64 with this induction: http://www.clubcobra.com/photopost/s...47492&cat=500). Anyone can interpret that as they may. More modern inductions are not of interest to me.

How many cars did they sell with Webers? Using your logic you could also install a dual 4-barrel single plane tunnel port in your Cobra because it was available "in the day" and someone thought about putting one in a Cobra and actually did.

You are dead wrong about your contention that a single plane manifold equipped with a Dominator has no low-end performance. I had one and have the dyno sheet to go with it. It produced more low-end torque than an 850 that was also dynoed on the same engine. The engine was very responsive on both road courses and autox events, which would be difficult if not impossible for 58 mm Webers. All this talk is cheap though, why don't you get your engine finished and share the dyno results with everyone and then demonstrate drivability at some open track events.

This is a video of my car with a single 1150 cfm dominator, does it sound like there are any low speed response problems? http://www.youtube.com/watch?v=mZaMFyZpKlo
H

[Excaliber]

Michael, yes, and impressive video!

It is quite possible the 58's do much better than the 48's. The dyno reports I've seen Webers vs Holley did show the Holley making more power at the top end. No doubt those were 48's, a much more common application.

All this 'number crunching' raises another question. The typical math formulas used to calculate the size requirements of a carb don't always apply, especially when it comes to race engines. I suspect the basic problem with the carb cfm math would be found in the VE area. Volumetric Efficiency, which is incorrectly ASSUMED in many cases. Using that formula one could easily conclude a single four of modest size is optimum, as far as CFM goes. I think it is clear, certainly for an FE, that 'more is better', like 2X4 or monster 58's when it comes to absolute power.

Work the CFM numbers for a 427 and I think you will find some where around 800 max cfm comes up! A number I just don't believe. From personal experience at the drag strip with three different size carbs (both carbs matching) I've found the best performance was around 1200 cfm (twin Holley 660's).

[Cobra #3170]

1600cc Formula Atlantic's used to run 50mm DCOE Webers feeding a 24.4 CID cylinder. A 58 mm Weber feeding a single 53 CID cylinder seems a little under carbureted, the more area the better to a point where velocity suffers.
A single cylinder that has a large plenum available to feed it along with multiple throttle blades will be less restricted and produce more power.

[Anthony]

Originally Posted by Cobra #3170

1600cc Formula Atlantic's used to run 50mm DCOE Webers feeding a 24.4 CID cylinder. A 58 mm Weber feeding a single 53 CID cylinder seems a little under carbureted, the more area the better to a point where velocity suffers.
.

Weber has a published graph recommending a specific size carb based on cylinder size and max rpm. For any given cylinder volume, the higher the rpm, the larger the carb needed, and the reverse is true, the lower the rpm, the smaller carb. I'll look tonight for their recommendations.

Originally Posted by Cobra #3170

1600cc Formula Atlantic's used to run 50mm DCOE Webers feeding a 24.4 CID cylinder. A 58 mm Weber feeding a single 53 CID cylinder seems a little under carbureted, the more area the better to a point where velocity suffers.
A single cylinder that has a large plenum available to feed it along with multiple throttle blades will be less restricted and produce more power.

The benefit of a weber, IR type intake, is the "ram tuning" effect, of getting greater than 100% cylinder filling from a specific runner length. Also, IR intake systems generally are easier to get equal fuel distribution as opposed to an opne plenum intake, which may not get as ideal air-fuel distribution.

[Michael4yah]

Ernie, Yeah Im thinking that that 850 single 4bbl is going to be maxed out with the stroker I was planning. Already bought the manifold though. When you add up the flow from all ports you can see why they invented the Dominator etc.
That video was a good one. Showed the braking of an all out racer too, Did you see how much speed he was able to scrub off while approching that white porsche and just before that switchback? I mean he went from over 200 to less than 40 in no time. And it was so smooth too. Just amazing stuff. Not the best cinematography and could have used a cleaner windshield and without the glare from the dash but still it was almost like being there. What did the Hot Rod Lincoln song say ? Telephone poles passing bye like a picked fence". Thats what those trees looked like. You could sense that if you left the track at that speed, youd end up a 1000' from the pavement. I can see why people come back year after year to Le Mans. I wonder if the old cars still get a chance to use that course during the year?

When it comes to setting up a car If I had my choice of anyone living or dead, I'd choose Ken Miles. If he said Webers work better than carbs Id take it to the bank. Ken passed more people than almost anyone and knew what it took to get the jump on the other driver and the choose the right angle of pursuit. I bet he used the quicker response and low end torque from those webers to edge out a lot of drivers. He was truely an amazing man and one of the worlds best drivers. Not nearly enough is ever said about him. Ok... Im off my soap box now.
Michael

[Excaliber]

I'm currently running twin 450 cfm Holleys with vacuum secondary. While a bit slower than the 660's, mpg and streetability are vastly improved over the 'full race' 660's.

[Byots]

nm .

[Cobra #3170]

Originally Posted by Byots

Tunnel Port heads and inductions only came into use near the end of Cobra production and had nothing to do with the Cobra. Bruce, I don't dispute that your monster cubic inch modern fuel injected engine would outdo my old technology, my interest is just more into the nostalgia, as the big weber inductions were a part of the development and history of the big block car and were optional race pieces for them. Webers were integral to the heart and soul of Ken Miles and Shelby American and that philosophy was being carried over from the small block to the big block cars, just ultimately not fully exploited, as with many other aspects of the 427 car. The big block Supercoupe is probably the best example of the pinnacle of Cobra withdevelopment that didn't get its fair opportunity in "combat", but that does not take away from its special place in the history of these cars.

Here is how the first big block car prototype engine came into SA from Ford by June of '64, equipped with an 850 Holley: http://www.clubcobra.com/photopost/s...=47517&cat=500 This was the aluminum 390 with aluminum high riser heads that were cast special just for Shelby.

Shelby American still had substantial control over its racing development activities at that point and, like the small block race engines, did some of their own development on the big block. It is believed the two styles of high riser weber intakes were specially made for the Cobra during this development period (the inline carb one to maximize hood clearance under the crown of the Cobra hood). Guys like ex Ford employee Ernie McCune (sp?) involved with racing activities said a batch of the 58mm webers were specially made for Shelby American in early '64 to use on the Cobra, which they installed on this prototype engine in place of the Holley: http://www.clubcobra.com/photopost/s...=47518&cat=500

This configuration notably outperformed the Holley, making reportedly over 500hp from only 390 cubic inches and tiny 390 sized valves. SA decided this was the optimal setup to run and went on to install this engine into the big block configured coupe (http://www.clubcobra.com/photopost/s...=47492&cat=500) for an assault on Lemans in '64 - it was to be Shelby's "secret weapon". The car was damaged in a transporter accident on the way to Lemans and returned to the shop, but SA employees were in awe of its potential. This engine, with webers, was later run in the flip top car.

Documentation from Ray Geddes to SA around August of '64 specified several big block race cars that were to receive these engines for the '65 season. Another Geddes memo dated about October of '64 (I haven't looked at these in some time) specified cast iron 427 blocks to be used in the race cars instead of aluminum, although Shelby would have probably still used the two aluminum ones he already had, as evidenced by the subsequent use of one in the flip top car in December at Nassau. Even after Ford changed the block specification from aluminum to cast iron, the 58mm webers were still planned on being used, as they were included in the FIA homologation paperwork at the end of '64/early '65. Early documentation just specified aluminum for the cylinder head material, leaving the option open of using MR or HR castings (the 58mm intake manifolds were only made for the HR head), whereas later in '65 just the MR P/N was specifically called out.

By the end of '64, Ford had taken much more control of SA's activities and all emphasis and key employees were diverted to the GT40 effort. With all the emphasis taken off the Cobra, the big block Supercoupe was starting to experience delays and problems. The writing was on the wall and finally when Shelby American was refused homologation around March or April of '65, the big block Cobra became a still born race car and many of the trick things the key SA race team members developed, like the big webers and big block coupes never had their chance at ultimate glory.

From the point Ford started having major influence over SA's operations in '65, SA employees became notably limited in what they could do with many of the engines. Race engines came in pre-assembled from Ford Engine and Foundry and SA employees in large part were not allowed to take them apart, including changing inductions. Bean counters and other Ford influence made the big block Cobras go out the door with more cost oversight than how SA had previously approached the small block cars (just look at the SA invoices....big block cars almost always had no options vs small block cars were often loaded with different equipment), also driven by Shelby's attention shifted to the GT effort. CSX3005 (a comp car) was a good example of this changing philosophy - it was being "optimized" by the factory, but when it came time to deciding who was paying, the car ended up being disassembled and the parts sold off or used in various ways. Earlier on, SA would likely have footed the bill just to get the visibility and promote Cobra racing success - now they figured they achieved what they wanted with the car.

The coil spring Cobras, including the comp cars, ended up being delivered in more basic form, with SA not as receptive to do as many add ons at the factory as they did with leaf spring cars. This was dictated from Ford's Ray Geddes mandate that the 427 just be a "customer car". Many things needed to optimize the cars for racing were left up to the owner to incorporate, with Shelby American offering most of the necessary items (including the webers) over the counter - although in many instances such specialty items were in short supply and SA would only freely "open up" availability to prominent racers. The 427 Cobra was being sold under a different mandate than modern supercars such as the Z06, etc. On the street, the Cobra in it's day was so fast relative to everything else, that SA employees had commented in discussions about parts outfitting that all the bells and whistles were not necessary and if someone wanted such trick parts they were available separately.

So, I hope this provides a fair picture of how special hardware like the webers fit in with the big block cars.

More weber comparative and sizing data to follow when time permits.

Note:
I was referring to my naturally aspirated 1967 dual 4-barrel tunnel port cast iron 425 CID engine vs. your Weber carb titanium rod "period engine" although they didn't have titanium rods for big blocks in 1967. I would be glad to compare dyno sheets. You would be at least 200 horsepower shy of my "monster cubic inch modern fuel injected engine" with those Webers and that comparison was certainly was not my intent.

My point is that because they offered something in a speed catalog, it doesn't make it period correct unless the car came with it, and none did. Any that actually had Webers had them added after delivery. If someone had a car that had a 1960's race history with them I suppose it would be fall in the realm of the Shelby Paxton cars but just putting them on a 3000 or 3100 series car after the fact is not period correct. You could only race them in an unlimited class and I suspect those instances were very few, and related to specific cars modified by their owners. 289s could race in production class with Webers, 427's could not. What racing customer would want to go out and get beat by a bunch of lighter mid-engine cars Webers or not. Essex wire is one exception based on your history lesson. There might be others, and again if they had a history of racing with them in the 60's it would make them sort of period correct. There were several cars that were chopped up to install 427 SOHC engines in 1967, does it make them period correct because some one did it?
I am waiting for that Weber powered dyno sheet. My car with the tunnel port engine and road race tires was timed at 11.20 @ 128 miles an hour at Detroit Dragway.
You could also provide a time slip for your Weber engine magic cam car if you don't want to dyno it.
I suppose you will be telling everyone how well 427 Cobra's handled
next if only the cars were equipped with all the options that were thought about and never released.

[Michael4yah]

Byots, Excelent coverage of the topic. You explained it within its historical context which to me is the most Important and interresting issue. You had to be around back in those days to understand how fluid the change was. Certainly the SA employees must have resented somewhat the intrusion of Fords execs into what was before a basicly free wheeling and open minded shop. It sounds to me those guys were encouraged to tinker with anything and everything attached to a Cobra. Can you imagine being part of that effort? I have lived here in So Ca. since '67 and no matter where you traveled back then you could see the enthusiasm and energy being poured into projects of almost every shape and size. The small shop was king and the industrial parks were their playgrounds. The Company that I worked for then dealt with lots of small machine shops throughout LA. Nearly all of them were involved in some sort of R&D. It wasnt unusual for me to be sent to pick up parts from these shops and while there youd see the employees huddled around their latest creations tinkering with them. It was Truely the golden age of manufacturing in America. We need to bring those days back. Its one of the keys that made our country great. I would have loved to see that big block Daytona run at Le Mans. I bet it would have done well. Peter Brock, you did yourself proud.
Michael

[Michael4yah]

[IMG]10262shelbyintakeadd-me[/IMG]The Cobra was a work in Progress, Not many were delivered exactly the same way. Ive talked to original owners and comapred notes. If Shelby sold the manifolds to the general public you can bet they were installing some of them on new ordered cars. Stop the nitpicking and pi$$ing contest. If Carroll Shelby himself cant tell you what every car came with who can?

[Cobra #3170]

OK got the message, since I actually had one of the very first orders for a 427 and lived through many of the problems associated with purchasing and owning these cars I thought that you might be interested in first hand experience, with engines and chassis, apparently not.