1st I've ever heard of the term, the "135 cars," a term for the first 50 Cobra Jets, the factory drag-racing cars built to introduce the new 428 Cobra Jet V8 to the public. The cars could run in the 13s on street tires, and 11s were only a set of slicks and traction bars away.

 

There are Cobra Jets and then there are Super Cobra Jets. Supreme among CJs, however, are the factory-built drag racing Cobra Jets. In late 1968, Ford built 50, from VIN 135007 through 135056. Due to the common first three digits, enthusiasts refer to these fastbacks as the 135 series.

Vinny was turning wrenches at Rye Ford when a transport parked itself outside of the garage bays with a brand new, shiny Mustang in tow. Since he doubled as the driver for the dealership’s drag racing program, he and colleague Benny Kaufman prepared the car with a three-point roll bar, traction bars, a scatter shield, and revised rear-end gearing.

Vinny Lyon had the right of first refusal on the factory dragster, and purchased it from Rye Ford in April 1969 for $3,605 (a little over $31,000 in today’s dollars). 

It came complete with drag slicks, an open exhaust, and a two-year warranty. It ran a best of 11.2 @ 118 mph in the Super Stock E class.

Fifty-five years later, Vinny still owns the car. No one has owned one longer

https://bringatrailer.com/2024/04/28/celebrating-4-28-the-135-series-cobra-jet-mustangs/

this one was bought by a collector, and only had 200 miles on it when he died around 2008, and his cousin had to deal with the estate as executor

It is one of the six lightweight Cobra Jet racers sent to Russ Davis Ford. 

Only two of those six were sound-deadener-delete with no undercoating, this CJ and the Gas Ronda racer.

A decal on the car puts it at the March '69 Fuel Gas Championship at Famoso Raceway in Bakersfield, and the '69 Springnationals.

https://www.hotrod.com/features/mscp-ford-135-series-cobra-jet-rare-f miles on it when inds/