Eric English
November 16, 2017

Ahh, the vaunted Boss 429… What’s not to like about this over-the-top muscle Mustang that ranks as one of the most talked about and desirable ponycars of all time? It’s got that wild semi-hemi NASCAR engine that is wall to wall impressive whenever the hood is opened. It wears the sheetmetal of one of the raciest looking cars of the muscle-era—the ’69-70 SportsRoof. It came equipped as a real musclecar should—but few Fords were —meaning mandatory four-speed, steep rearend gears, limited-slip dif, and big 15-inch wheels and tires. On the cusp of its January 1969 debut, the Boss 429 Mustang appeared to be the musclecar incarnate, and buff books of the day were ablaze in the hype. And then the big Boss hit the streets…

What we all know now, is that the Boss 429 was a bit of a performance dud when it was released to the public. In reality it’s not that it didn’t perform well—magazine tests finding very low 14s in stock configuration. Rather it’s that the Boss ‘9 didn’t make good on the killer performance that was anticipated. For example, FoMoCo brethren with the 428CJ usually turned out to be quicker, while the competition had multiple offerings that were equal or better performers at lower cost. But our mission here isn’t to dis on the Boss 429, rather it’s to set the stage for its modified potential.

The wall to wall Boss 429 engine looks even nastier than most thanks to dual quad Holleys. The NASCAR cylinder heads are rumored to have once been part of the Wood Brothers team inventory, and feature fully hemispherical combustion chambers.

While Ford wasted the opportunity to maximize the Boss 429 in street form, the package certainly accomplished its primary mission—legalizing the Boss 429 engine for NASCAR racing. And when green-lighted in March of 1969, the new engine simply dominated that realm, running away with the 1969 NASCAR Grand National championship. But what about Boss 429 Mustangs that weren’t left stock; were they competitive on the streets and strips of Anytown USA? At least a handful of Ford dealers spent considerable time working the Boss for all it was worth, including Tasca Ford, Foulger Ford, Tom Larkin Ford, and the dealer who campaigned our particular feature car, Nelson Ekdahl Ford in Minneapolis.

According to Pete Peterson, the original driver of the Nelson Ekdahl Boss 429, the car was received by the dealer in May of 1969, and underwent immediate prep for drag strip use. Peterson was a dealership mechanic at the time, and was thus knee deep in the work to get the car ready. “We thought we were going to get some parts support from Ford, but it didn’t turn out that way. In the end, we had to go through the learning process of what worked on our own. The first time out at Minnesota Dragways, the NHRA officials didn’t know what class to put us in, as they had never seen a Boss 429. The first two weeks we ran in A/Modified Production, then we were re-classified and ran the rest of the season in Super Stock/F. Equipped with 7-inch slicks, 5.14 gears, custom headers, and a NASCAR cam sourced by our parts manager, we never lost a race in that class (SS/F).” Peterson says he recalls ETs being in the 11.80s at 118mph, and yet the effort with the big Boss lasted for just a single season. Nelson Ekdahl sold the car in November 1969 for $5,500, with Peterson explaining “with a young family on the way and on my mechanic’s pay, I didn’t have enough money at the time to buy it myself, but sure wish I had.”

1969 Boss 429 Mustangs were some of the most well-appointed musclecars of the era, all coming with the Interior Décor Group, high back bucket seats, floor console, rim-blow steering wheel, tachometer, and clock.
The interior of Leenstra’s Boss is mostly original, down to the quartet of Stewart Warner gauges that Peterson installed in the dash pad all those years ago. The Hurst shifter is also akin to what Peterson used to bang through the gears, though sans T-handle and line-loc.

From that point forward, the trail on this Boss goes quiet until around 2006, when a customer of Boss 302 enthusiast Randy Ream bought the car and brought it to Ream for restoration. “It was an odd duck when it arrived at my shop, wearing old and incorrect Grabber Blue paint and powered by a 428CJ. From the condition of the fuel in the tank, I’d guess it hadn’t been run in 15-20 years.”

While the customer acquired the parts, Ream dug in and stripped the car to the bone. “It was pretty clean at its core, and so the body and paint were straightforward. I had a local shop near me in Pennsylvania spray it in the factory Wimbledon White using PPG base/clear. Pete Peterson supplied us with some period photos and we duplicated the way they painted the hood in matte black—much like a Mach 1 or Boss 302 would’ve been.”

Of course we’re used to seeing the blackout hood/cowl treatment on ’69 Mach 1s and Boss 302s, but Boss 429s weren’t privy to the same treatment originally. However vintage pictures show that the Nelson Ekdahl team added the blackout prior to going racing, and so it was duplicated during restoration.

Ream emphasized using as many of the original parts of the Boss as possible, and with 20-some thousand miles showing on the odometer, many of the original parts were indeed salvageable. Of course that doesn’t hold true for the engine, since it was long gone for who knows how long? The current mill isn’t quite true to the car’s early Super Stock configuration, rather it’s a rowdier piece that was sourced from a NASCAR stash, including the block and heads—the latter with full hemispherical combustion chambers. Since dual quads weren’t available on a factory built Boss 429 Mustang, they weren’t allowed for Stock or SS class racing either, and yet the setup here seems a natural for a full boogie Hemi powerplant. Dawson Racing headers channel the spent fumes rearward, while forward motion is put in play with a proper big in/out Toploader and a 9-inch N-case rear featuring 4.30 gears.

Boss 429 enthusiast Bob Leenstra bought this car at auction in 2010, largely because of its unique and preserved racing provenance. Leenstra already owns a 135-series ’68 428CJ Mustang drag car, and figured the Boss would make for a great straight-line pairing. With the hard restoration work done, Leenstra put his own stamp on the effort by replacing the white lettered street rubber with a set of wheels and tires inspired by the original racing rolling stock. To that end, he opted for new American Racing TTOs, 15x5-inch up front and 15x7-inch in back. The rubber is likewise new but vintage in appearance, featuring 7.10-15 BFG Silvertowns and M&H 9.0/28.0-15 slicks. As they say, if looks could kill…

In an age when we don’t typically see Boss 429s restored to anything other than stock condition, the Nelson Ekdahl drag car is a rare and interesting sight. While it wasn’t a national level competitor, its history is clearly worth preserving and promoting, and we dig seeing it in its near-competition configuration. Like any street or strip warrior of the era, the factory delivered a combination which was just a starting point in the quest for going faster. Modifications could liberate untapped potential, and it’s here—rather than in stock form, that the Boss 429 Mustang began to be the animal it was predicted to be.

Sitting in the Nelson Ekdahl garage circa 1969, surrounded by Torinos.
Driver/mechanic Pete Peterson launches at Minnesota Dragways against one of many 396 Camaros he competed against.


The Boss 429 in NHRA Competition

We explained in the main text how a smattering of Ford dealers around the country tried their hand at developing the Boss 429 for hot street and strip use, with one of the more detailed efforts as follows. Hi-Performance CARS magazine ran an enlightening story in their 11/69 issue, reporting on a stock class Boss ‘9 campaigned out of Tom Larkin Ford in Flat Rock, Michigan. The story diagnosed some of the Boss ‘9s maladies, reporting sloppy blueprint specs, the mismatched S-motor juice cam, and a poorly functioning hoodscoop that actually hindered performance. In addition to common drag modifications such as spring and shock alterations, the Larkin Boss was fitted with 4.71 gears, JR headers, a full engine blueprint, and the T-motor solid lifter cam. These mods helped the Boss, running in B/Stock, to 12.09 at 118.21 on slicks, with more development still to come. The magazine mentioned the current B/S class record of 11.85 at 119 held by a ’67 427 Fairlane, so the effort seemed to be on a good track.

Interestingly, this same article explained the B/Stock classification was due to a NHRA 435 horsepower refactoring for Boss 429s with the T-motor solid cam, while at the same time dropping S-motor hydraulic cam cars to 370 horsepower (5 less than advertised) and a C/Stock assignment—where 428CJ cars were fierce competitors. CARS reported that the Larkin Boss picked up nearly half a second of ET by ditching the factory air cleaner assembly, the stock ram-air system proving so ineffective that it actually starved the engine for air. This was a real handicap in that NHRA rules didn’t allow for aftermarket designs, while other cars in class had effective scoops, not to mention more compression and carburetion, which was limited by class rules as well. In the end, it appears the Boss 429 Mustang fell victim to what it was: a hasty homologation effort to get the engine legalized for NASCAR racing. Had Ford devoted the time and effort to develop the Boss as a street or NHRA Stock and Super Stock competitor, there’s no telling what its credo could’ve been. Clearly the basis for a monster performer was in place—the supporting hardware sadly failed it.

This is the way the Nelson Ekdahl Boss 429 appeared when it arrived for restoration at Randy Ream’s shop in 2006.