This will only fit if you have an AOD or AODE transmission in your early Mustang
Or if you have a foxbody with a AOD transmission
MMHP4335
Brand: Hughes Performance
Manufacturer's Part Number: MMHP4335
Part Type: Transmission Fluid Dipsticks
Product Line: Hughes Performance Locking Trans Dipsticks
Dipstick Entry: Transmission case
Dipstick Mounting Location: Bellhousing mount
Locking: Yes
Dipstick Tube Included: Yes
Dipstick Tube Material: Steel
Dipstick Tube Finish: Gold iridited
Dipstick Handle Material: High-temperature nylon
Dipstick Handle Finish: Natural
Quantity: Sold individually.
Notes: This dipstick is designed to fit 1980-1991 AOD transmissions, however it may not fit when being used as an OEM replacement due to the amount of variations in OEM designs. Modifications to attachment or dipstick routing maybe required. Bellhousing mount transmission dipsticks are recommended for dragster, street rod, or other applications with ample clearance to the bellhousing. These are not recommended for vehicles with minimal clearance between the bellhousing and firewall or transmission tunnel.
Transmission fluid and pavement are a very bad combination, especially when you're trying to race on that pavement. So, keep your transmission fluid in the transmission, where it belongs with Hughes Performance locking transmission dipsticks. These dipstick-and-filler-tube assemblies are manufactured to exacting tolerances, come complete with all mounting tabs, and are available for a variety of domestic rear-wheel drive vehicles.