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Thanks Guys - that is great information. As for the throttle bodies belonging in a museum, I think it well matches the owner! Now if I can only find numbers 3 and 4....!? Good luck with that.

Panteradoug - I would be interested if there was any information on the original use. I fibbed about the Pub and Porsche. That was for CV joints....!

These things have been gathering dust for the last thirty years and I could imagine someone seeking the restoration of an historically perfect classic may well value them if they matched the original build specification of their vehicle. 

Bosswrench _ I am going to start looking for a right-angle adapter to mount the two 48 DCOE side-draft Webers on a 351-C 4bbl intake. As soon as I read that I thought it would be a  possible way forward. Brilliant.

Tony ( Edge ) was very kind and  generously showed  me the EFI setup  on his extreme Pantera yesterday . It was similar in form to the Borela arrangement but had external injection ports on the carburetors. The fuel management he has built system is quite complex and the EFI system was more than a bit intimidating for a newby like me. He is building a ultra lightweight 427 dart block to go into it , so still a major work in progress. I certainly was in awe of what he has done and now have some appreciation of the complexities of a first class EFI install, and what it would entail. 

I cannot thank him enough for his hospitality and sharing his knowledge.  

Yup. They look just like them.  Very pricey though. That seems to be coming around again for me David? I feel a project coming on. I've got to go looking at CPU combinations. I don't like the manifold that Borla is offering for their set up as the linkage requirement on a Pantera is unique which is why the cast in linkage tower is on the Hall and Detomoso manifolds.

You need to mount the carbs/throttle bodies with the fuel inlets outboard so that you have reasonable throttle access running down the middle of the manifold.

On a Pantera it is hard enough to work on them to begin with and changing the access to the linkage could be the straw that breaks the camels back?

The original design considerations for the mounting on the Pantera are correct for the car but if you mount them on a different car like for instance a Mustang you want to reverse the entire linkage design and run the carbs in parallel and side mount the throttle. That is where sometimes the "experts" disagree.

I've run them both ways on both cars and perhaps the criticism against my advice is that others don't understand that I have a unique perspective on that subject?

You might find my next comment moot but I have found that there is a loss of power across the rpm scale if you mount the carbs in parallel. The reason is that you change the line of sight from the throttle plate opening to the valve.

Seems silly but the power change is very measurable.

There were several vendors that had the adapters for the side drafts listed. Hall had pictures of them installed on a Pantera. Probably the car that you are thinking of Boss?

You need to note though, that the point of the down drafts was that you were able to achieve the optimum distance to valve of 4.5 inches and direct line of sight to the intake valve. You can't do that with adapters or with the side drafts.

You can do that if you take the FI side draft intake manifold and rifle bore the throttles thorough the manifold mounting flanges. To this day I have not seen anyone do that.

I am not versed on the IDF's. The Cobra guys aren't either so I'd have to search for that chapter of expertise and am wondering if those "authors" are still with us?

I do know that they were on the earliest factory Cobra race cars with 260's. That's like one or two cars. Where they were "sourced from" I don't remember and I'd be relying on the accuracy of early magazine articles and hope that the author mentioned that and that I've just forgotten?

Last edited by panteradoug

There is a lot of mis-information on this thread. The first large downdraft Weber carb was the 45 IDM (M=Maserati) developed for the 1957 Maserati 450S race cars. These carbs were also used on very early competition Cobras. Then came the 48 IDA (A=Abarth) which were a modification of the IDM and slightly larger bore. This is the common downdraft Weber of the Cobra era. For a number of years, Weber stopped production, but now they are making them again in Spain.  Most versions of this carb have only two progression holes and are a little "tricky" to make run smoothly on the street. We always add a third progression hole even with vintage race engines. I am not sure, but the current production IDA's may have three holes. The 48 mm bore limits the effective use of this carb to about 350 cu. in. engines. These carbs can be bored to 50 mm to help a little on larger engines. Ford financed a very limited series of 58 IDA units for the 255 Indy engine of 1962. They also appeared on some larger displacement Can-Am engines. Next comes the 40 and 48 IDF (F=Fiat) units. These are far more sophisticated carbs as they were designed for street use from the start. They have three progression holes and diaphragm accelerator pumps instead of the old piston pumps of the IDM/IDA series. They are easily tunable for street use and are less expensive than the IDA series. The downside of this carb for race usage is it has poorer interior streamlining than the IDA and therefore does not flow as much air at full throttle. Ford specified 48 IDA's with 37 mm venturis for street applications and 42 mm venturis for race usage in the day. Today, we bore the venturis to 45 mm for a modern vintage race motor. We use 38-40 mm venturis on 289 street engines. IDF's can easily use 40 mm venturis on street 302-351cu. in. engines.

I will review the details on the manifold but I think that is one that has cast in a vacuum plenum?

Even if finances permit, I don't want to switch manifolds, just replace carbs with EFI to clean up the idle.

The 4v intakes and A3 intake ports don't line up. I haven't seen a "high port" IR manifold other then the Hall that I am using.

Modifying a 4v means closing up the bottom of the port 5/8" and raising the top 1/4". That makes either welding or epoxy filler necessary.

The original Weber look-a-like throttle bodies were a Dynatec design. Those throttle bodies in particular have had machining accuracy issues which created idling issues with them. Supposedly Borla corrected that when they bought out the line?

I have a quote here from Dynatec for $2,800 for four. Borla doubled the price.

What CPU to use with them now seems to be the big issue. Apparently the self learning CPU's are blamed for erratic running conditions. That's another issue to be dealt with. We'll see.

Last edited by panteradoug

Doug, it would be pointless for you to buy a new manifold. In fact, in my opinion, you’re better off with the one you have. That Borla manifold has a large vacuum plenum. You really only need a plenum that large if you have a MAP sensor and an IAC sharing the plenum. I don’t have an IAC so I have a very small MAP plenum. With your manifold, you can choose the size of plenum you use, as well as choose where you want to put it.

@davidnunn posted:

Doug, it would be pointless for you to buy a new manifold. In fact, in my opinion, you’re better off with the one you have. That Borla manifold has a large vacuum plenum. You really only need a plenum that large if you have a MAP sensor and an IAC sharing the plenum. I don’t have an IAC so I have a very small MAP plenum. With your manifold, you can choose the size of plenum you use, as well as choose where you want to put it.

Thank you for that info David. I already have an oxygen sensor installed (for an A/F ratio gauge) and a vacuum manifold installed for the vacuum gauge.

The linkage stays the same and I can reuse my stacks and screens. So I need the throttle bodies and cpu.

Which CPU to use is the most controversial and item of disagreement.

There was some discussion on the Holley CPU since Borla is part of the "Holley Family" now.

Doug, I can only tell you what my experience has been. I have a Holley Dominator ECU. I went with the Dominator because I wanted to use dual O2 sensors without an add-on module and I wanted the capability of blending both types of EFI logic; speed density and Alpha-N. I also wanted flexibility in what I used to generate the cam sync. and crank signals. I didn't really care whether Holley's tech support was any good but I wanted to buy an ECU that was manufactured by a substantial company, that was likely to still be in business in ten years. That being said, the proof is in the pudding and I'm happy to report that my EFI system works better than I ever expected it to.

I've attached a video taken out of the rear window of my Pantera. Turn your volume up! Notice how little throttle it takes to get the car moving along. Also notice how smooth the idle is. I have a solid roller cam and you can roll a golf ball through my mufflers but you'd never know it because EFI smooths the motor completely. I'm not sure everyone would think that's a good thing but I do!


Videos (1)

Yes but without being my own dyno shop I have to review all comments of people who have done or attempted to do this regardless of whether or not they actually understand or know what they are doing.

You for instance are using different throttle bodies. There have been comments that I must presume have significance that the Borla Weber look-a-likes have a different fuel injector location above the throttles plates then another Borla design which injects under the throttle plates and as such the CPU program APPEARS inadequate to deal with the differences.

One comment was that with the Borla Weber look-a-likes, the Accell CPU was the solution. So at the moment I need to look for specific comparisons to what I want the finished product to be?  I can't spend my life looking for a solution.

At this moment I would anticipate ONLY a CPU that controls the fuel delivery system and not the ignition, leaving the ignition alone and as is.

Interestingly enough is that there is no comment on the Jenvey's at all?

It is ENTIRELY possible that those who have said, "the car 'runs great' ", haven't got the foggiest idea what they are talking about, are looking at or experiencing? On the other hand, it probably is also likely that there is not or never will be a complete 100% solution? For me, I could also go back to an imperfect carburetor solution as a fall back.

Certainly it is common place for racers to swipe at each other and treat the opposition as if they are a bunch of retarded no nothing individuals. That is a concern with competing "tuners" that I have as well.

Even so, I am not convinced that the "expert tuners" are actually able to or have done a side by side comparison of both throttle body types and CPU systems to compare the best combinations. I think in all fairness, that would be a very difficult if not impossible task.

They certainly are experts on some of the CPU systems and therefore have their ideal selections that they have been able to tune in their eyes successfully. No one here has the capability of NASA.

For me, so far Borla's and Jenvey's are on the map. I have not discovered other Weber look-a-likes. The Jenvey's appear to be more reasonably priced as well at $719 each v $1,200 each fo the Borlas.

Last edited by panteradoug

Doug, don’t get too caught up in discussions about one ECU or another. Once you find a CPU that has the features and inputs/outputs that you want, a successful installation simply depends on your ability to navigate the software. All the ECU does is tell the injectors when to squirt fuel and for how long. If someone tells you they solved a tuning issue by changing ECU’s, it simply tells you that they couldn’t navigate the software that controlled the previous ECU. Pro tuners rarely have such issues.

I'm talking with Pantera Electronics about the compatability of the P-E Ignition Controller and what is necessary to adapt it to a CPU.

It may simply be that it needs a module to communicate with the CPU to tell it when the ignition is firing.

The question is if one already exists as a plug in or I need to search the Universe for one. At the moment it doen't sound like there is one or if the original designer ever had that as a consideration.

Progress is slow but it is progressing in the right direction. A plug in would be the simplest but why make things simple?

I'm told that on the CPU part all that is needed is a "trigger" port.

I'll agree with you in that every thing new initially seems to be a steep learning curve. I've recently felt my brain growing sideways. That's ok. I still have lots of hair to cover the head profile distortions it creates. I was always ugly anyway so not many notice it.

I don't know. It's been in there for quite a while and typically with Jon's products, once you install them, you never have to look at them again. EVER.

That's usually a good thing but when you need to remember the details, you need to call on Indiana Jones to do some archeological investigations. Then you run into Nazi's. I hate Nazi's.

I have the early case design P-E-IC. I didn't like the MSD case design of the newer ones. I didn't ever want to be associated with MSD again in any way, form or even shape. Once bitten twice shy. Three times bitten then you need a pre-frontal lobotomy. Did I just admit that?

Last edited by panteradoug
@davidnunn posted:

Does the PE Ignition controller have a tach output? That might be all you need for a simple batch fire EFI system. If you want to go sequential, you’ll need a cam sync signal and a crank signal.

Jon reports that the tach output wire is TACH ONLY. My early IC needs to have a dedicated trigger wire added to it.

In sorting through the available CPU's the information is as cumbersome and confusing as ever.

That is simply going to take some time to filter out the spam.

@Percy posted:

Garth- do you have any pictures  of the throttle linkage set up required for the two side-draft webers arrangement when replacing a 4-bbl Holley?

I am having trouble seeing how it could be laid out.

Unfortunately I do not.  I only found those online but have not seen one installed in-person.  Some more Google searching may yield a result.

Found a great chart in a 1988 publication "Weber Carburetors" by Pat Braden.

He sorts the Weber family by the number of throats and shafts , float position and the style of actuation. I have not found anything similar to describe the groups of Webers in my searches. He attributes the IDFs to either Ferrari or Ford application , which is interesting. Just thought I would share this for  interest.

weber family chart


Images (1)
  • weber family chart

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