In September, 1969, the Special Vehicles team at Ford proposed the "1970 1/2 Composite Mustang Program". This "super muscle car" would be a mid-year offering with planned production to start in January or February of 1970.
By this time, they were no longer making Shelby Mustangs. The BOSS 429 program was almost at an end as they satisfied the homologation rule for NASCAR. In addition to this, Chevrolet was going to introduce a mid-year body style change for the Camaro, giving them a jump on the new styling. The Composite Mustang proposal would fill these voids.
It was originally called the "Composite Mustang" because it combined existing parts from 4 different engineering programs:
- Mustang Sportsroof body from the BOSS 429 program - This body had special accommodations for a larger engine
- Shelby fiberglass front end - provided a preview of the 1971 styling
- 429 Super Cobra Jet engine - a new engine, not planned for use in the Mustang until 1971. It also had improved performance and lower production cost over the BOSS 429 engine.
- Mercury Cougar XR-7 dash and instrument panel - provided a unique appearance as well as a full set of gauges (the Mustang instrument panel could not accommodate a Tachometer with Oil pressure and Ammeter gauges)
Two prototypes were built (a 4-speed and an Automatic) and they were sent to the drag strip for testing. After this testing, the program was renamed to "1970 1/2 Mustang Quarter Horse". It was determined that a production vehicle, with minor modifications for strip, would have an average ET of 13.022 seconds at 109.89 MPH. Impressive even by today's standards for a production car. Especially impressive on 1970 rubber.
Both prototypes are rumored to be in the hands of collectors. Fortunately these very unique Mustangs did not meet the fate of most prototype cars. If you have any information on the "Quarter Horse" Mustangs, or their history, we would like to know.
Grabber Blue Quarter Horse
Red Quarter Horse