Holley 780 Carburetor used on the 429 SCJ
Note that the automatic trans version (D1ZF-9510-XA) used the solenoid and the 4 speed version (D1ZF-9510-YA) used a dashpot.

D1ZF-9510-XA

Used on 71 429 SCJ Mustang with C6 transmission. The auto trans used a solenoid as shown below.

Used on the 71 429 SCJ Mustang with 4 speed transmission. The 4 speed uses a Dashpot (shown below). Bracket at center and installed view at right.

Choke Tubes and Stove

The two photos at left show the choke tubes used on the 429 SCJ Mustang with the Holley 780. The choke tubes inserted into the open ends of the choke stove (various views). The "U" shaped portion was installed into the intake manifold where it was exposed to heat from the exhaust gas routed from the heads to the intake manifold. Vacuum from air entering the carburetor drew fresh air into the top choke tube, where it then passed through the heated U shaped stove installed in the manifold, then into the choke housing to heat the choke coil and cause the choke to open. The heated air was then exhausted from the choke housing

Click this link to Dan Davis's Special Write-up: The Rochestor Carb used on the 429 CJ

Rochestor Carburetor (various views)

Rochestor Solenoid  - The correct version for the 429 CJ Mustang/Cougar (red/yellow wire) is shown above. The photo at right shows how the solenoid threads into the bracket and adjusts with a lock nut to keep it in position. Also, A/C cars used the solenoid and non A/C cars used a dashpot.
 

GM Part Numbers on the Quadrajet: 7040285 = Manual Trans w/AC, 77040286 = Auto Trans w/AC, 7040287 = Manual Trans w/o AC, 7040288 = Auto Trans w/o AC.
 

Various Views of Rochestor Choke Setup 
 

                  

Choke Covers

The 429 4 speed choke cover is shown at left and the  429 C6 choke cover is shown at right.     

Carburetor Gasket

Shown above is an original carburetor to intake manifold gasket for the 429 SCJ with the Holley 780 (Part #C9AZ-9447-D). It was approximately 1/8" thick. The CJ with Rochestor used a D0OZ-9447-A gasket.
 

Carburetor Attachment Nuts

Original Ford carburetors used the smaller nut (shown at right in each photo) which requires a 7/16" socket on the studs that attached the carb to the intake manifold. The larger nut (left in each photo), which  uses the 1/2" socket is the common non-original replacement.
 

Throttle Brackets

The 429 CJ with the C6 automatic used a spring (attached to the back of the throttle bracket into a small eyelet) to stabilize the transmission  kickdown rod. The 4 speed and C6 SCJ throttle brackets are shown at right. Note they do not have the eyelet for the spring.

Throttle Cables

The 429 Mustang/Cougar version is very difficult to find now if you need one. Before 4/1/71, it was part #D1ZZ-9A758-A . After 4/1/71, it was part #D1ZZ-9A758-G (below). The cable was 23.75" long and had a brown paint daub as shown. Installed view shown at bottom.