I worked for Chrysler from 1964 thru 1969. I worked with the Special Performance Group, under the direction of Dick Maxwell and Tom Hoover. I worked on and helped prepare the 1966 D-Darts during the spring of 1966.
The Race Group focused on tech support for guys like Sox & Martin, Dick Landy and Arlon Vanke. Little thought was given to the 273 Commando.
Chrysler Performance wasn't really interested in putting together a Super Stock program for 66', as they wanted to focus on the Street Hemi. Several racers and dealerships pressed us for a program, some even mentioned putting a program together for the small block Darts and Cuda's. That struck a chord with some of the top exec's in the Performance Group.
In December 65' and early part of 66', several racers on the west coast and southern areas were having moderate success with their 273/235 hp Commando small blocks (competing in H/Stock). The complaints or questions coming back to Chrysler was that they needed more power to truly be successful. The only true successful small block race team at that time were the "Golden Commando's". The were running 14.90s' to 15.10's in their H/Stock Darts and I/Stock Cuda's.
The truth is Chrysler was disappointed with the performance of the 273 H/Stock Dart cars at the 66' Winternationals in February 66' at the Los Angeles County fairgrounds. Chrysler had dominated the S/SA and top Stock classes, but failed miserably in the lower junior stock classes. The Performance Group was asked to come up with a formula for improving power in the 273, and quickly, as to be ready for the Springnationals or at least the Summernationals. We picked the brains of the sponsored racers and top dealerships, and received pretty much the same response; better head flow, bigger cam, better intake design and increased carburation.
The question was, How much horsepower increase?, and What class would we be running?
We had plans of putting together a stronger motor with TRW forged pistons (higher compression of course), and o-ringed block to ensure a sound-seal for combustion, as well as improved oiling system with a high volume pump and windage tray. For valve lift we suggested a .480 lift solid-lifter camshaft, one that Sig Erson cams had designed (I'm not sure of the duration), as well as improved valve spring tension. Special rocker arms with chrome moly pushrods were also planned. Since the bore size of the 273 was limited 3.63"
we could not install larger valves in the heads without serious modification (notching of the block. So we suggested bigger ports heads for flow, as somebody in Chrysler engineering had a proto-type of these heads already completed. For intake a host of ideas came, a cast iron dual quad unit with Carter carbs, an aluminum dual-plane high-rise, a cast iron dual plane, an an aluminum single-plane X-shaped port unit. Our group was just focused on the motor only. The drivetrain and body unit were already set and approved, by Dick Maxwell or Tom Hoover.
The original D-Dart program was initiated in late December of 65'. The original plans were to build a special high performance 273 engine. Exact horsepower requirements were not in the fore front. As our ideas were thrown around. We thought that we were building a 273 package for both the Dart and Barracuda. The original moniker for the 273 higher horsepower unit was Super Commando (later to be used with the 67' 440 HP engines). Soon were told that we were building a special 273 for the Darts only, the first time a special engine was to be used in a specific car, not shared by both Dodge and Plymouth.
The race program heads wanted to tackle its direct competition, the 289/271 HP "Hi-Po" Mustangs. The "Hi-Po" Mustangs were dominating the D/Stock classes at the local dragstrips during late 65' and early 66'. The light Mustangs were running 13.60's to 13.90's with moderate modifications, and usually dominated the class trophy's. The D/Stock record at the time (January 66')was around 13.20. I'm pretty sure it was held by Ronald Grey out of Terre Haute, Indiana, with a 65' Pontiac GTO convertible with a 389/335 HP engine.
The race groups plans were, build approximately 50 to 60 specially prepared Darts (modified engine and tricked suspension)to compete in D/Stock. Build another 250 to 400 (depending on demand) to be available for street use. The street designed cars would have the same engine components, only different rear-end gears (4.10's)and street-capable suspension and street/strip headers with easy access dump-offs. The street cars would be available in white, black or red, the interiors would available in red only. The factory-prepared race cars would be available in white only, with red interior. A special D-Dart moniker was designed for the front fender, right under the 273 High Performance emblem. The original design called for a 18" wide by 1 1/2" high V-shaped fiberglass hood scoop to installed, with a manually-controlled cable to open an 8" round disc door mounted under the hood. It could add an additional 7 horsepower to the power-plant when exceeding 70 MPH. All cars would be shipped with 14" x 6" Cragar S/S chrome wheels with 7.50 x 14" tires.
The original plans from January 66' were highly motivating. The exhaust system was first planned with a specially designed high-flowing cast iron manifold/header style unit, dumping into the large single-pipe exhaust pipe. We knew most of the factory-prepared race cars would probably have the exhaust systems yanked by the racers, and tweaked with the headers. Just how Doug Headers got involved, is still am mystery. Their header unit was OK, but not really a race-type unit, it was truly a street-header with small collectors (under 3"). It would turn out to be OK for the street designed D-Darts, but not the race groups factory cars. We argued either cast iron exhaust manifolds (which would be yanked), or proper race headers which Jardine Headers had designed 1 5/8" primary with 3 1/2" collectors (under chassis units), or Hooker Headers who had designed a fenderwell unit with the same size tubing.
For some reason all ideas or suggestions were shot down.
We sent NHRA a proposal plan on the net horsepower for the tricked up engine, and NHRA told us that they would factor the motor
in at 290 horsepower, putting us in the C/Stock class, which would make us in direct competition with our own cars, the 62' and 63' 383/343 HP dual quad 383 Plymouth and Dodge cars. Dave Kempton was running a 62' Plymouth in C/SA, running 13.05's, and the last thing
we wanted is to run against our own cars.
The key to getting the 273 to run, was to improve intake flow and carb CFM's. The problem as you know with the 273 is that it would die at top end. Low-end and mid-range were fine with the little torker, but at the end of third gear the motor would float out. We were hoping to
put an Offenhauser dual-plane aluminum high-rise intake on the motor with a Holley 700 carb.That combination would prove awesome, as a little known racer (John Vesperman)was having success with that combination in his 65' C/MP Dart in Oklahoma. He was running high 12.00's
with a tricked up 273, and cleaned up the C/MP class in the southwest, eating the tricked up289 Mustangs and 283 Corvette's. Unfortunately, putting that intake manifold on the engine would increase another 7 to 10 HP on the motor, putting us over 295 rated HP from NHRA.
The factory's plan was to tackle D/Stock, and the maximum horsepower output of the motor had to peak at around 280, to fit in that class with the weight break. As we had sent out bulletins and passed out information on our plan, a buzz went around the dragstrips, that Chrysler was building a superstock project for D/Stock. It was met with excitement from numerous racers, who wanted to get a factory-prepared car for less than $2800 (basically a budget-racers dream). The truth is, the factory-prepared cars would be
dedicated to a selected few experienced racers and drag-race teams, and race-oriented dealerships. Only 50 to 60 drag cars would be built, meaning only a handful would be available to regular racers. Our initial response was that about 95 pre-orders came in from
the dealerships, and about 45 pre-orders came in from current racers.
Just as about the time we were planning to go forth with the project (around March 1966) a major thing developed. The D/Stock record (which was 13.20 or so) which was within range for our 273, was crushed. Barry and Ernie Mueser out of East Redding, PA. ran their 61'
283/270 HP dual-quad Corvette to a 12.90 time. Seems that somebody from Chrysler got under their skin at an NHRA points meet, because they had lost to a factory-backed racer Dave Kempton in his 62' C/SA Plymouth three times in a row in National events. Not only did
the Muesers break the D/Stock record, they even went quicker than the C/SA record. With the record now below 13.00, it was .30 lower than our estimated goal of 13.20, we contemplated whether to go forth with the D/Dart plan. I think sometime in March or April
of 66' we decided to go forth with the project, at about the same time, the Muesers ran a 12.78 with their Corvette. That time was not achievable with our 273, and we knew it. Right then and there, the D/Dart program was basically over. Chrysler was not about to go
forth with an unattainable race program, also the first plans were in the process for the 67' RO Hemi Belvederes and WO Hemi Coronets for SS/D Super Stock project.
With over 100 pre-orders in house, Chrysler had to go forth with some kind of project, to satisfy the anticipated racers. The last thing Chrysler wanted to do (if you knew the factory) was to return money or cancel pre-orders. So we prepared a water-downed version of
the D-Dart, nowhere what it was supposed to be. First, the Doug Headers that were used, were preordered for the street-designed D-Darts.
Chrysler had ordered 200 sets of the street-type under chassis units back in early 66', so they had to utilize the units anyway. As for camshafts, Chrysler did not want to spend extra dollars on the Sig Erson unit, so they put out a bid for 50 performance-based
camshafts, and Camcraft (a little known camgrinder from Maryland) won the bid with a 495. intake lift and .505 exhaust lft, 284 duration bump-stick. I think they charged Chrysler $30 per shaft. The cam would add about 20 horsepower over a stock unit. The valve
springs utilized were 240 lb. spring tension Racer Brown units, actually the springs were leftovers from a Chrysler marine engine project. As for the Holley carbs, the race program felt they had to add a nice bell and whistle teaser to the engine, to justify the special
moniker. In reality, it was a cheap way to increase horsepower, In fact the engine only put out about 255 horsepower, which would have put the car in F/Stock, and would have been more competitive. The only reason the headers were installed (to add about 15 to 20 horsepower),
was that we had already purchased the units. It was really fake horsepower.
We argued that we should not produce a half-baked project, but somebody up there in the head office wanted the cars out there. Really it was cover your butt project. Though there are claims that 50 cars were produced in April of 66', the truth is about 25 or so were
built. To this day, I have only seen (2) D-Darts race. I have never seen a true D-Dart at any Mopar meets. We did test run one the cars before delivery, and with 7" slicks and the 4.86 gears we were able to get the Dart into the 14.60's. Car Craft tested a Dick Landy tuned
Dart back in the spring of 66' and supposedly ran a best of 14.33. The truth is, that car was tweaked by Dick Landy before Car Craft got their hands on it. The motor was pulled, and the components were balanced and blueprinted, the heads were done over by Kenyon. The
suspension was tweaked by Landy, with 6-cylinder torsion bars up front and Super Stock leaf springs for the rear. Still all in all, 14.30's for a 273 with moderate race parts is respectable.
Rumors floated around that Dick Landy got a D-Dart to run in the 12.00's. In truth, Dick Landy never got and never ran a D-Dart, he did however run a 273/235 HP Commando Dart in I/Stock, late in 66' and early 67'. That car ran 14.80's and was fairly successful on the west coast local circuit. However, it did not knock down any doors at any points meets.
For the D-Dart program, kudo's to the guys out there who tried and were somewhat successful in D/Stock. Several racers got their cars into the high 13.00's, and only Ted Spehar was able to get the Dart down into the low 13.00's. Most of the D-Dart purchasers though were
stuck with mid 14 second cars. One wonders what would have really happened if were able to put together a true package, TRW 11.5 high compression pistons, factory-balanced components, improved oil system, double roller chain, bigger port heads, Sig Erson valve train, an OFFY
aluminum intake and air induction to feed that thirsty Holley. 12.90's would have been within reach. Dick Landy had said it to us best, forget about D/Stock, build a 273 engine with a rated horsepower of 250 horsepower, run G/Stock, and he'd kick ass all day long.
He suggested calling it the DL-Dart (Dick Landy Dart). He had it all set, with a moderate lift solid lifter cam from Racer Brown, Forgedtrue lighter-weight pistons, and an aluminum high-rise intake manifold, that's it. He would trick the suspension for racing, and guarantee 13.90's out of the box. Nobody at Chrysler would let that happen.
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COPYRIGHT 2007 BY ALAN LEWIS