The First 260/289 Competition Cobra Weber System

[CompClassics]

I thought I’d share these photos with you of the first competition Cobra Weber system with 48 IDM Weber carburetors…..48 IDM Webers were used on all SAI 260/289 competition Cobras including the first three 289 FIA Cobras and Daytona Coupes. These carburetors were used into 1964 and were replaced in the field by 48 IDA carburetors. The 48 IDA Webers were first thought to be installed on CSX2323 from new.

[CompClassics]

This is that 48 IDM Weber system…

[CompClassics]

More photos….

[cobrakiwi]

John
Do you think the small block under that setup in your first pic is a xhp 260?

[1985 CCX]

Originally Posted by cobrakiwi

John
Do you think the small block under that setup in your first pic is a xhp 260?

Why Craig, do you know who has one?

[twobjshelbys]

They sure are cool looking! Both on and off the car!

[cobrakiwi]

Originally Posted by 1985 CCX

Why Craig, do you know who has one?

Hey Jeff
I sure do!

[CompClassics]

Also note in the photos the valve covers that have been modified so that you could see the valve train operating too. It is obvious in the photos that there is more than just “test & tune”, seems more like development engineering.

[1795]

I imagine that they had to do quite a bit of development to get them to run right and understand what the valve train was doing to optimize performance. A little less messy to have the tops of the valve covers removed, as opposed to no valve covers.

Jim

[Dan Case]

Originally Posted by 1795

A little less messy to have the tops of the valve covers removed, as opposed to no valve covers.

Jim

The rocker arm covers shown have clear windows in metal frames attached.

Some time later Ford was using vacuum formed clear plastic covers in the engine development program. I have held a pair of them in my hands that were claimed to have come from SA when they closed the California works.

[LMH]

John, what’s the black cover for in the center of the manifold?
Larry

[twobjshelbys]

Clear covers reminds me of the early hard drive days. We did clear covers for drives, sometimes for troubleshooting but mostly for trade shows. We had special firmware that moved the actuator around so they could see it. Eventually the physics of the plastic top resulted in too much vibration and the whole system became too unstable to work.

[NROTOXIN]

Originally Posted by LMH

John, what’s the black cover for in the center of the manifold?
Larry

A Grant Duel coil Flamethrower distributor. I had one in my 1956 chevy gasser.

[Dan Case]

Originally Posted by NROTOXIN

A Grant Duel coil Flamethrower distributor. I had one in my 1956 chevy gasser.

The marketing brand name on the top covers during the Cobra use period said "SPALDING" on them. Same design unit over time, different branding at different times.

Spalding marked top covers included small raised text consisting of: “SPALDING” twice near opposing edges and the notation “PAT. PEND.” along the edge. The information on the top covers for marked Grant units included raised text consisting of: a very large centrally located cast in stylized letter “G” logo bracketed by the name “Grant” twice and the notation “PAT. PEND.” along the edge. Yes, Grant marked models were sold as Grant® Flamethrower™ units.)

Cobra owners doing detailed restoration work hunt covers marked with Spalding's information.

[Dan Case]

Originally Posted by LMH

John, what’s the black cover for in the center of the manifold?
Larry

I am not John but you would have to go back to late 1962 early 1963 and ask somebody in the Shelby work's engine shop. Look closely at the dynamometer cell image and you will just barely see the plate and fasteners installed already six decades ago. The blue arrow is pointing to the plate.

[LMH]

Originally Posted by Dan Case

I am not John but you would have to go back to late 1962 early 1963 and ask somebody in the Shelby work's engine shop. Look closely at the dynamometer cell image and you will just barely see the plate and fasteners installed already six decades ago. The blue arrow is pointing to the plate.

Thanks Dan! I saw that too but I couldn’t figure out what that was for! Looks to be an access plate for something.
Larry

[Dan Case]

John is showing you, in the factory engine testing picture and his new pictures, are 48 IDM1 model carburetors. They are extremely rare and were not common in 1963.

Short course, a 46 mm IDM design was created as an upgrade from to the mid 1950s 45 IDM model. A few 46 IDM models were reworked into 48 IDM models for a Maserati Formula 1 effort. All this circa 1958-59. At this point my research leads to Ford Motor Company asking for a 48 mm unit for their sports and race car engine programs and the 48 IDM1 was created. There must not have been large numbers of 48 IDM1 marked units made based on ones I can account for decades ago or now. The 48 IDM5 replaced them as a general go to independent runner down draft carburetor for all kinds of race cars with all kinds of engines until the 48 IDA and 48 IDA1 both got to Shelby American circa late March or early April 1964. Not every race team or car abandoned the 48 IDM1 and 48 IDM5 models, at least not as soon as they could have and some never did. Shelby American used quite a few 48 IDM5 carburetors 1963-64.

The significant difference in design between 46 IDM, 46 IDM1, 48 IDM, and 48 IDM1 and the 48 IDM5 was in the throttle spindle support. The early units did not have ball bearings to support the throttle shafts. 48 IDM1 carburetors I have studied all had pressed in plain bronze bearings (a.k.a. bushings). The new 48 IDM5 (and the 46 IDM2) model used Conrad type radial contact ball bearings to support the spindle shaft and included the spring loaded leather bearing seals people are familiar with in several mid 1960s and later E. Weber carburetors.

[CompClassics]

Chaparral used the IDM series carburetors all the way into 1968.

[CompClassics]

Larry,

The black cover is covering a machined hole that was used for an oil filler / vent tube, twist on style with two ears. While restoring the assembly I had to removed the cover to restore that area, I have several photos of the work being performed, and then re-rivet the cover back on.

[CompClassics]

This is similar to the tube I referenced in the above post, I have seen a photo of the manifold with the tube installed but for the life of me I can not locate it and as soon as I do I will post it.