Whither 1966 D Darts for Stock

[bill dedman]

Good post, Dwight!

However, this sort of thing has been going on for so long, and is so entrenched in the M.O. of NHRA tech, it's a case of the horse having left the barn YEARS ago, with the advent of 327 intake manifolds on 283's, aluminum heads on select engines, 904 T-Flite internals inside BIG cases, and now, metric 200 transmissions in cars that were built YEARS before the transmission was even dreamed of...

Yep, I think the horse is long gone, and he ain't comin' back....

More's the pity...

[Paul Ceasrine]

My fellow D-Dart friends,

This is what came on the 66' D-Dart 273/275 HP engine.
The block was a standard 273/235 HP HiPo, with a forged steel crank.
The pistons were standard 273/235 HiPo, 10.5-1 compression with a
2-step rise in the piston (Not domed, as some people think).
The pistons were full-floating.
Standard oil pump. (No windage tray or Hi Volume pump)
Standard 273/235 Hi Po steel timing chain.
The camshaft was not a .520 lift racer Brown as some people think. Though Racer Brown did develop cams for the Max-Wedges and
Race Hemi's, they did not provide the camshaft for the 273/275 HP
D-Dart. The camshsft was provided by Camcraft, out of Easton,
Maryland. The lift was .495 intake and .505 exhaust, with a 284* duration. That cam grind was the same Camcraft recommended for their 273 marine performance engines. How they got involved is still a mystery.
The heads were stock 273/235 HiPo, but the valve springs were
Racer Brown, 260lb. rated tension.
Stock steel valve spring retainers.
Amazingly, the stock steel push rod (yes bendable and breakable) were utilized.
The cast iron (YES!) cast iron intake was a stock unit. The carb venturi
holes were bored out from 1 1/2" to 1 11/16" to accept the larger butterfly openings of the Holley carb, The machining of the intake was performed at the factory. The D-Darts that left the LA plant did not require a carb=adapter plate. In general, the low-plane X-runner shape
intake was a piece of garbage. Small runner ports and low-plane was good for low-end torque, but at top-end the air-flow suffered.
The carb was a Holley #4160, 600 cfm vacuum secondaries.
Air-cleaner was specially designed low restriction-type.
Distributor was a dual-point unit, that was modified (vacuum advance unit was removed), to provide for mechanical advance only.


Paul

[Paul Ceasrine]

D Dart information.

The D-Dart was built in April 1966, in preparation to put cars out there
before the 1966 Sringnationals in June.
The 275 HP rating was advertised by Chrysler, not set by NHRA.
The lb/hp rating factor of the car was 10.71.
The factor ratio of D/Stock in 1966 was, I think, 10.40 to 11.20
The 273/235 HP cars had a rating factor of 12.63.
They fell into the F/Stock class, 12.00 to 12.80.
I might be slightly off on the NHRA factors. Back then NHRA factors
were by .70 or .80, instead of today's.50 factor.

Paul

[Paul Ceasrine]

D-Dart,

If anyone wants to contact me about D-Dart info and/or several photo's of
an original D-Dart, you may.
e/mail: jvshank@connectnc.net
As for the photo's. I have several from 1971, of a woman racer
named Lori Kane. Her white Dart was lettered Kandy Kane across the doors, with a red and white striped Candy Cane painted in between the
lettering. Her car was sponsored by Garrison Shell, Garrison NY.
D-Dart was painted on the front fenders.
If you look closely at the windows, the car is classed in H/Stock..
From the information that I have gathered, the D-Dart 275 HP rating was
re-factored to 255 in 1971, re-classifieing the car from F/Stock to
H/Stock. Now when NHRA dropped the factoring of the car from stock is still a mystery.

Paul C

[Steve Hagberg]

D Darts:

Well I just dusted off my 1966 rule book and discovered a couple of interesting things. First, the classes and weight breaks were not uniform. Stick cars started at S/S, then A/S down through O/S. But the automatic cars stopped at J/SA. The super stock class was 0.00 to 6.99, then as follows: A, 7..00 to 8.69, B, 8.70 to 9.49, C, 9.50 to 10.59, D, 10.60 to 11.29, E, 11.30 to 11.88. and on down the line. How they came up with these breaks is a mystery. Another interesting note is that if your car wasn't in the classification guide, they just weighed your car, subtracted any fuel at 6 lbs/gal and divided by the factory advertised HP, and that was your class. There were no NHRA 'FACTORS' for HP, just factory advertised ratings. So the D Darts fell in the D class at 10.60 to 11.29 lbs/hp. Thsi sure brings back memories of a simpler time!

[Paul Ceasrine]

Steve,

Great job in posting the 1966 stock class factor ratios.
I guess my mind is not that out of tune, I was only off a little on the factor ratios.
If you could, would you give me the factor for F/Stock in 1966.
It started at 11.89, according to your guide, what ratio did it end at.
in 1966 I ran a 66' Barracuda 273/235 HP, and it fell into F/Stock, at the high end of the weight break.
In 68', we ran a 67' Barracuda 273/235 HP that was classified in J/Stock, when the factoring changed. 12.50 to 12.99 for our class.

Thanks,

Paul

[Steve Hagberg]

Paul:

The F class went from 11.89 to 12.49, and then G stock went from 12.50 to 13.99 seconds. The bad part of the old system, as I'm sure you remember, is that if your car didn't fit in at the low end of the class you just had to carry the extra weight ( you couldn't lighten up to the minimum). Running off the national record was also a problem if you happened to be in a class that had been bombed by a fast car. All these problems eventually led to the formation of Bracket Racing. Interesting that 43 years later we're still arguing over how to make class racing fair.

Steve

[dart4forte]

Originally Posted by Paul Ceasrine

My fellow D-Dart friends,

This is what came on the 66' D-Dart 273/275 HP engine.
The block was a standard 273/235 HP HiPo, with a forged steel crank.
The pistons were standard 273/235 HiPo, 10.5-1 compression with a
2-step rise in the piston (Not domed, as some people think).
The pistons were full-floating.
Standard oil pump. (No windage tray or Hi Volume pump)
Standard 273/235 Hi Po steel timing chain.
The camshaft was not a .520 lift racer Brown as some people think. Though Racer Brown did develop cams for the Max-Wedges and
Race Hemi's, they did not provide the camshaft for the 273/275 HP
D-Dart. The camshsft was provided by Camcraft, out of Easton,
Maryland. The lift was .495 intake and .505 exhaust, with a 284* duration. That cam grind was the same Camcraft recommended for their 273 marine performance engines. How they got involved is still a mystery.
The heads were stock 273/235 HiPo, but the valve springs were
Racer Brown, 260lb. rated tension.
Stock steel valve spring retainers.
Amazingly, the stock steel push rod (yes bendable and breakable) were utilized.
The cast iron (YES!) cast iron intake was a stock unit. The carb venturi
holes were bored out from 1 1/2" to 1 11/16" to accept the larger butterfly openings of the Holley carb, The machining of the intake was performed at the factory. The D-Darts that left the LA plant did not require a carb=adapter plate. In general, the low-plane X-runner shape
intake was a piece of garbage. Small runner ports and low-plane was good for low-end torque, but at top-end the air-flow suffered.
The carb was a Holley #4160, 600 cfm vacuum secondaries.
Air-cleaner was specially designed low restriction-type.
Distributor was a dual-point unit, that was modified (vacuum advance unit was removed), to provide for mechanical advance only.


Paul

What I find interesting is that the manifold off the marine 273, the bores are 1 11/16". Had access to one week before last and it measured 1 11/16" so it's possible that's what they used on the D 273.