The Chevrolet 454 LS6 was designed specifically to make the 1970 Chevelle SS the baddest Bowtie muscle car ever produced, and we're happy to report that the mission was a complete success. Similarly, the Buick 455 Stage 1 was only ever destined for the 1970 GS 455 as the car's nameplate would indicate. Iconic rides from the Golden Age of American Muscle have signature engines and, for the most part, they were always intended to receive those iconic big-blocks.
There were also some classics with defining engines that kind of dumb-lucked their way into them. The compact second-gen Plymouth Barracuda was actually banned by Chrysler from ever getting a 426 Hemi, but thanks to a little finagling, the 1966 Hemi Barracuda factory drag car became a reality as well as a legend. Believe it or not, Ford actually has a classic-era ride with a signature engine that it was never supposed to have, and how it came to be seems like a twist straight out of an M. Night Shyamalan movie.
A Pony Car With Not Enough Ponies
1964 was arguably the most exciting and consequential year in American automotive history, with the Pontiac GTO launching the muscle car craze and in mid-model year the Ford Mustang inventing the pony car. While the Mustang was part of the Golden Age as a sporty, affordable ride that appealed to younger buyers, it was by no means a muscle car. Initially, the top engine option for the 'Stang was a 271-horsepower 289 cubic-inch HiPo K-Code V8. That wasn't awful, but didn't have the oomph of, say, the GTO's 348 pony 389ci Tri-Power V8.
In 1967, Ford let the 390ci V8 loose on the Mustang, giving it a much-needed boost to 320 hp and 427 lb-ft of torque. By that time, however, all the cars on the street had access to terrifying amounts of power and the Mustang was still a last-place loser in any red light challenge. Even with the upgrade, a '67 Mustang GT was pulling ETs in the low-15s to high-14s, and that was as unacceptable back then as it is now.
Even Shelby Can’t Help
Ferrari-killer Carroll Shelby recognized the Mustang's shortcomings in the performance department and started building souped-up versions he sold under his name as Shelby GT350s. With a bit of weight reduction, improved suspension, and various performance upgrades, Shelby got the Mustang's 289ci V8 up to 306 hp, which improved acceleration, but not significantly. A '65-'67 Shelby GT350 ran the quarter-mile in 14.5 seconds, which was kind of like standing still next to a Hemi-powered Mopar. Even when he stepped up to the 428 big-block with the '67 GT500, it was still a 14-second car and by that year you either ran in the 13s or you were laughed at.
Big-Block Blackout
Ford had some awesome big-blocks in the classic era, but for whatever reason, never thought of dropping them under the hoods of Mustangs. There was, of course, the legendary 427ci "Side Oiler" V8 that made legends out of the '66 Thunderbolt and '66 Fairlane R-Code factory drag cars, with an underrated 425-hp output.
The "Cammer" version of 427 was so insane that it got kicked off the NASCAR tour until it could be homologated, meaning they had to be sold in passenger cars in certain numbers. Ford could have very easily sold some Mustang GT 427s and kept that 600+ hp engine dominating the closed-circuit, as well as giving enthusiasts the car they were screaming for, but didn't.
The Forbidden GM Engine That Engineers Built Against All Orders
It cost $4,160 in 1969 ($36K today) with only 69 built through the COPO program.
Tasca Ford’s 428 Mustang GT
Bob Tasca Sr. was the owner of Tasca Ford in Providence, RI, which was a high-volume/high-performance dealer. He, too, was concerned that the Mustang was way behind in the Horsepower Wars and actually offered buyers upgrade options. Unlike Yenko Chevrolet, which put bigger engines into underpowered Camaros, Tasca Ford improved the stock 390 of the Mustang with performance parts. He was constantly in Ford's ear about making the Mustang more powerful and then a bit of serendipity gave him the chance to show corporate what he was clamoring for.
Tasca had a Lime Gold '67 Mustang nothcback demo car that he souped-up for his daily driver. One night, his head mechanic and sons took the car out for a joyride and proceeded to blow up the engine. Tasca loved that car and was going to replace the engine, when it struck him that he could drop in a 428ci Police Interceptor and that's just what he did. This was no ordinary 428, however, as Tasca had his service department Frankenstein it with high-performance parts from the 427 Side-Oiler. There is no documentation on how powerful this engine was, but it made the Mustang "Go Like Hell" which Carroll Shelby could never do.
Enter the 428 Cobra Jet
Ford caught wind of Tasca's 428 Mustang, which he dubbed the KR-8 "King of the Road '68" and invited him to their proving grounds in Dearborn, MI for a demonstration. Ford threw everything they had at the car, but Tasca's car smoked them all. Impressed, Ford set in motion the development of the 428ci Cobra Jet V8 that was ridiculously underrated at 335-hpand 440 lb-ft of torque. Realistically, this engine was more like 410 hp and the 13.5-second ETs a car equipped with could run prove that better than a dyno.
For 1968, Ford did a 50-unit run for a Mustang fastback 428 Cobra Jet lightweight factor drag cars, the first one of which went to Bob Tasca Jr. More importantly, the 428 Cobra Jet was an engine option in '68 and finally gave the Mustang the power it had always deserved. The 428 was introduced mid-model year, which is kind of a Mustang tradition, so only 1,044 were ordered, but in '69 when word got out, Ford moved 13,073 units.
Mach 1 Muscle Car
Also in 1969, the Mustang officially became a muscle car. A major redesign added some length and width to the '69 model, giving it a more aggressive stance and in the newly minted Mach 1 SportRoof fastback. This was the car that replaced the GT as Mustang's top performance trim, and it certainly stepped into the role with a purpose.
Combined with a 428 Cobra jet, the '69 Mach 1 was the first Mustang that could turn heads like a Trans Am and run with a school of Barracudas. The once playful pony car was suddenly a serious street brawler, and it was a huge hit with Ford fanatics, selling 72,458 cars versus around 25,000 GTs in 1968.
Ford's Most Powerful Classic Muscle Car Wasn't A Mustang
The most powerful Mustang in the 60s was the Boss 429, but this limited production model was substantially more powerful.
429 CJ Had Another Intent As Well
Ford began developing the 429ci V8 as a race-only engine they hoped to use in NASCAR, where it was destined to live under the hood of the Torino and Mercury Cyclone. Having come off the 427 ban, they thought it would be best to sell it in a production car to qualify for competition. Rather than make an awesome Torino or Cyclone special edition, they did the coolest thing ever by shoe-horning them into some fastback Mustangs, creating the completely bonkers '69-'70 Boss 429.
Limited to just 1,358 cars, the Boss 429 cranked out 375 hp and 450 lb-ft of torque, making it the most powerful Mustang of the time. Also, due to its rarity, the Boss 429 quickly became the most collectible pony car and is among the most expensive classic muscle cars today.
John Wick’s Boss 429 is Missing an Inch
When some thugs jacked John Wick's ride and killed his puppy, it set off a revenge spree that saw probably thousands of dead bodies across four amazing movies. In the first film, John Wick identifies his car as a '69 Boss 429, but in reality it's Mach 1 with a 428 Cobra Jet.
Many have pointed out this error, but usually say something to the effect of the producers tried to make the Mach 1 look like a Boss 429, but even that's untrue. The car is very clearly a Mach 1 with no effort whatsoever to give it Boss 429 details. The franchise did finally redeem itself with the spin-off flash-back series The Continental, which, among other things, traces the origins of John's signature ride and acknowledged it as a Mach 1.
Mustang 428 Cobra Jet Collector’s Market
The 1968 and beyond 420+ big-blocks are the most valuable regular production Mustangs on the market. You can find a great condition '67 fastback with a 390 for under $50k, but a cherry Boss 429 starts at half a million and just keeps going up. A '68 GT 428 Cobra Jet has a Hagerty Concours condition value of $156,000 for the fastback and $280,000 for the drop-top. A '69 Mach 1 428 Cobra Jet is a little easier on the wallet because it was produced in more abundant numbers, but still tops out at $150,000 for a show car.
The late-'60s Mustangs are very popular with the restomod crowd, so there's a ton of six-figure auction sales, as well as the $200k and up Shelby GT500KRs, but the most expensive factory original '68 Cobra Jet we could find on Bring a Trailer was a fully-restored GT fastback that sold for $117,500 last year, which is actually a nice price. There haven't been any bank-breaker '68 Cobra Jet cars like the Boss 429, but it is rarer, and one exceptional example could rewrite the record books.
Sources: Bring a Trailer, Hagerty