Although the majority of Quadrajets were manufactured for GM vehicles, a handful went to Ford, and they were unique to the 429 and 429 Cobra Jet. You can't install just any Quadrajet on a Ford because they have a different throttle linkage and kick-down lever. Ford Quadrajets have a straight-in fuel line design intended for Autolite/Motorcraft screw-in fuel filters, unlike their GM counterparts. Rochester didn't stamp a Ford part number into Ford Quadrajets. Only a tag was used, which makes these carburetors like a needle in a haystack unless you know what you're searching for. Look for a GM number in the casting - 7040285, 7040286, 7040287, or 7040288. Anything outside these numbers is not a Ford application, according to Pony Carburetors.
Ford Carburetor ID Guide
When you're as passionate about carburetors as Jon Enyeart, you learn everything you can about them. Jon has been in the carburetor business for 30 years and messed with them even before that. His Ford Carburetor Guide is an exceptional tool if you're searching for the right Mustang carburetor. You can get a copy by calling Pony Carburetors or through their website.
This is the Carter YF one-barrel...
This is the Carter YF one-barrel carburetor used only on '67-'69 California emissions and '70-up 200ci sixes. The YF is a simple metering rod design that will work on any 170 or 200ci six.
Although the Autolite 1100 gets a lot of attention for its extensive use on Ford sixes, it wasn't the only six-cylinder carburetor. Carter is a name we associate with Chrysler products of the era, but Ford also used its share of Carter carburetors. The Carter YF first saw use on California emissions 170 and 200ci sixes in 1967. In '68-'69, only 170 and 240ci sixes got the Carter YF, which means you will never see one on a Mustang. When the Autolite 1100 was phased out in 1970, Mustangs got the Carter YF on 200ci sixes. The Carter YF is a little squat-box one-barrel carburetor with metering rod function like the larger Carters. It is a better carburetor than the Autolite 1100, although Jon Enyeart tells us the YF suffers from a poor accelerator pump design, which gets fixed during a Pony Carburetors' restoration.
The YF carburetor does not have a Ford part number on the body. Your best shot is the carburetor tag if it remains. There is a Carter number stamped into the body, which helps. You're looking for a Carter YF #6051. YFs came in 150, 170, 187, and 200-cfm sizes.
Here's the Carter RBS for...
Here's the Carter RBS for Ford 250ci sixes. It has the same basic bore design as the YF with a completely different fuel bowl configuration. It has the same shortcomings as the YF too-accelerator pump issues that Pony Carburetors corrects during restoration.
The Carter RBS was used only on the Mustang's largest six-cylinder engine, the 250ci six, from '70-'73. Like the Carter YF it replaced, the RBS is a metering rod design actuated by intake manifold vacuum. And like the YF, it also struggles with poor accelerator pump function. A Carter number #2191 is cast into the RBS body.
In 1972, Carter began producing these carburetors with the words "Mfd. By Carter for Motorcraft," which makes them easy to identify. Only one size-215 cfm-was produced.