Match Race 1972 ~ 'Duster 340 vs 'GTO 400'

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69 Cuda 440

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Match Race 1972

'Duster 340' 340/240 HP

vs.

Pontiac 'GTO' 400/250 HP

Low-Compression Performance Cars
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fs_1972_Plymouth_Duster_340_rvl.jpg


th
 
In 1972, the NHRA went the way of 'Pure Stock' for Stock Class.

No Headers, no nothing.

Wide 60 Series tires were permitted, as well as Traction Bars.

The NHRA factored the '1972' Cars by their 'advertised' Horsepower.

Both the 1972 'Duster 340' {340/240 HP} and 'Pontiac GTO' {400/250 HP}
fell into E/Stock {13.00 to 13.99 Wt/Hp}





 
My friend lived this one...

He could pull 2 -3 car lengths outta the hole,, and then watch that Goat get closer and closer in the rear-view mirror,... and

.. pass him in the last 50 ft.. time after time... sheesh..
 
I'm going with the Pontiac on this one.
My wife had a 1972 340 Duster when we married. It wasn't very quick.
Granted, it was loaded every option on it.
With a 3.23 gear, it only ran 15.70's.

I was working for a guy that had a 1972 GTO 400. He had bought it new.
It seemed to be faster than the wifes Duster.
He had never ran it thru the 1/4 for times.
 
1972 Pontiac GTO {Base Price = $3300}

It was actually a Lemans, but with the GTO 'option' {$335}.

The 'standard' 400/250 HP engine.

Available in a Hardtop {#3450 lbs.} or Sports Coupe 'Post/Pillar' {#3510 lbs.}

Only 5807 built {5673 Hardtops} and {134 Sports Coupe}.

Surprisingly light with a 400 Engine, as the GTO came through with the nicely-styled
Fiberglass Hood with long low-profile Scoops.
 
Factory advertised ratings.

340
240 HP @ 4800 RPM's
290 Ft/Lbs. of Torque @ 3600 RPM's

400
250 HP @ 4400 RPM's
325 Ft/Lbs. of Torque @ 3200 RPM's
 
Weight difference

'Duster 340'.......................... #3165 lbs. {Shipping Weight}

'GTO 400' Hardtop................. #3450 lbs. {Shipping Weight}

Both were available with 3.55 Gears.

Mopar 4-Speed {A-833 Late Series}.......... 2.44 / 1.77 / 1.34 / 1.00
Pontiac 4-Speed {'M-22' Close-Ratio}....... 2.20 / 1.64 / 1.28 / 1.00

This is not 'even' close.

In 1973, the NHRA re-rated the 340/240 HP to 270 HP = Classed in H/Stock = {11.50 to 11.99 Wt/Hp}
In 1973, the NHRA re-rated the 400/250 HP to 273 HP = Classed in J/Stock = {12.50 to 12.99 Wt/Hp}
 
Thanks P, Cool thread :wink:.

Just to let you know how much softer the low comp 400's were, my buddy put 100+ runs on a 69'GP and was consistently in the 14.60/14.70 range @ 97+mph w/3.23 gears. After 120k or so it got real tired, so we located a low mileage 72' 400/250 out of another GP. With no other changes, it went 15.30's @ 92/93 mph.
 
O-M-R

Out of the Blue, I got an idea on this Match Race......:cheers:

Magazine Results----------------------{4-Speed}--------------- {Automatic}

'Duster 340' {w/3.23 Gears}........ 15.08 @ 91 MPH ............. 15.17 @ 89 MPH

'GTO 400' {w/3.55 Gears}........... 15.65 @ 90 MPH.........................................
'GTO 400' {w/3.31 Gears}................................................... 15.83 @ 87 MPH

Sounds about right.........
 
The difference between the two doesn't surprise me at all. The overall results.....that's another story...lol. Damn magazine test's.:D
 
Not directly related, but i recall, before i dumped my 2000+ magazines, that Hi-performance CARS tested a Petty blue 72' 340 Cuda that went mid 14's @ the mid 90's? If my memory serves me correctly, the 8.5 340's could still get it done. Might have been great conditions and close to sea level, but.....

P.S. Found the numbers....lol.

1972 Plymouth Barracuda (HPC)​
340ci/240hp, 4spd, 3.91, 0-60 - 8.0, 1/4 mile - 14.35 @ 91mph​
.​
Here's a couple more.......Hard to rationalize some of these tests....​
.​
1972 Plymouth Duster (HPC)
340ci/240hp, 3spd auto, 3.55, 0-60 - 8.2, 1/4 mile - 14.45 @ 95mph​
1972 Plymouth Barracuda (CD)​
340ci/240hp, 4spd, 3.55, 0-60 - 6.9, 1/4 mile - 15.50 @ 91.70mph​
 
Wow,, that surprises me,.. I woulda expected the mph for the goat to be faster than the Duster.


thnx very much.. I really enjoy these threads....
 
O-M-R

Those 'Duster 340' results, probably with 3.23 Gears.

On the 1972 340, NHRA has

* Compression ............... 9.32 to 1
* Camshaft..................... .429" / .444" Lift ~ 268*/276* Duration ~ 44* Overlap ~ 114* LSA

* Cylinder Head .............. #3418915 ~ 1.88" Intake / 1.60" Exhaust
* Combustion Chamber.... 64.7 CC {Minimum} ~ 71.0 CC {Factory}

* Piston Type................... Flat w/Notches
* Depth........................... -.054" {In the Cylinder}
* Head Gasket................. .036"

* Carter Thermoquad....... 800 CFM

The Mopar Sales/Specification Brochure states 8.50 to 1 Compression.
 
69 Cuda 440 said:
O-M-R


* Compression ............... 9.32 to 1

* Combustion Chamber.... 64.7 CC

* Depth........................... -.054" {In the Cylinder}
Click to expand...

These three numbers are interesting. I guess I'm not surprised as Nhra had to be pretty liberal with the blueprint specs considering how far factory tolerances could vary.
 
The NHRA bumped the 1972 Duster 340/240 HP all over the place.

NHRA..........HP...........Stock.....Super Stock
1972........ 240 HP........E/S.........SS/O
1973........ 270 HP........H/S.........SS/L
1974........ 270 HP........H/S.........SS/L
1975........ 275 HP........H/S.........SS/L
1980........ 275 HP........H/S.........SS/L
2002........ 270 HP........H/S.........SS/L
2003........ 285 HP........G/S.........SS/K
2004........ 285 HP........G/S.........SS/K
2008........ 289 HP........F/S.........SS/J
2009.........293 HP........F/S.........SS/J
2010.........293 HP....... F/S.........SS/J
2011.........299 HP....... F/S.........SS/J
 
inertia said:
Wow,, that surprises me,.. I woulda expected the mph for the goat to be faster than the Duster.


thnx very much.. I really enjoy these threads....
Click to expand...

I suspect while the 400 with a 3.75 stroke gave it a decent low end and mid range, it was done early with it's really mild cam. The 340 however still had it's standard grind that surely helped it pull upstairs a extra 500 rpms or so.
 
Last thing the GTO saw before the rods fell out.
 

Attachments

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OldmanRick said:
Not directly related, but i recall, before i dumped my 2000+ magazines, that Hi-performance CARS tested a Petty blue 72' 340 Cuda that went mid 14's @ the mid 90's? If my memory serves me correctly, the 8.5 340's could still get it done. Might have been great conditions and close to sea level, but.....

P.S. Found the numbers....lol.

1972 Plymouth Barracuda (HPC)​
340ci/240hp, 4spd, 3.91, 0-60 - 8.0, 1/4 mile - 14.35 @ 91mph​
.​
Here's a couple more.......Hard to rationalize some of these tests....​
.​
1972 Plymouth Duster (HPC)
340ci/240hp, 3spd auto, 3.55, 0-60 - 8.2, 1/4 mile - 14.45 @ 95mph​
1972 Plymouth Barracuda (CD)​
340ci/240hp, 4spd, 3.55, 0-60 - 6.9, 1/4 mile - 15.50 @ 91.70mph​
Click to expand...

1972 Duster 340....... 14.45 @ 95 MPH.........3.55 w/Automatic


141301-500-0.jpg


High Performance Cars Magazine {May 1972}

'Still a Potent Performance Car Despite the Low-Compression'

'The 'new' 1972 'Duster 340' still has the Mini-Hercules Engine plant, but Horsepower is now down to 240 HP,
due to Lower-Compression as a result of restrictions in emissions from the EPA. The 1972 340 now has an
advertised 8.5 to 1 Compression-Ratio, down from 10.3 to 1 in 1971.'

'The 240 HP rating is calculated at 4800 RPM's, which is down from the previous years 1971 340 which had
an output of 275 HP @ 5000 RPM's. Despite those advertised Horsepower numbers, most 'performance-minded'
drivers know that the 340 Horsepower numbers were purposely under-rated from Mopar.'

'The 'new' Low-Compression Cast Pistons are now found further down in the Cylinder, as the Piston-Pin locations
have been re-positioned .100" higher in the Piston boss, lowering the Compression height. The Pistons are still
Flat-Top slugs with Valve-Reliefs {notches} to allow for cylinder/valve burn-off.'

The 340 still has 'Forged Steel' Connecting-Rods and with the less friction Full-Floating pins. The late-year 1972 340
will now have a Cast Crankshaft, which is lighter than the previously utilized Forged Unit, but is not as strong.'

'The Mini-Hercules is still equipped with the responsive Hydraulic-Lift Camshaft, which has a 268*/276* Duration
and 44* Overlap. And the 'stiff' Valve-Springs balance out the Valve-Train with the durable and reliable stamped-steel
non-adjustable Rocker-Arms permit the Engine to easily crank out over 5000 RPM's.'

'The 1972 340 Cylinder Heads {#3418915} are now equipped with smaller {1.88"} Intake Valves, but the Heads still
retain the same #915 'J-Head' Cylinder and Port configuration and size, as well as 1.60" Exhaust Valves. The 'J-Heads'
have good Port Volume which provides for excellent Port Flow across the full RPM chart.'

'The factory rates the Cylinder Head combustion-chamber at 71 CC's, and this provides for an EPA accepted lower
emission discharge at lower RPM's. But, these Heads can be milled down to 64.7 CC's by removing {.032"} which will
gain an additional {.83} in Compression, and the 340 will still idle fine with the higher Compression.'

'The Cast Iron Intake Manifold {#3614025} is a bit bulky at #50 lbs., and the casting is very rough. The Plenum-opening
is rough-surfaced and poorly cast, and the Port-Runners are unequal with high-spots. But the Spread-Bore throttle
bore openings and 360* Dual-Plane design do provide for an adequate Flow thru the Runners.'

'The now proven Carter Thermoquad Carburetor with the 'thermoplastic' center housing provides for 28% cooler temperature
in the Fuel Bowl. The reduced temperature of the Fuel translates into higher engine efficiency, which allows for increased performance. The 800 CFM Thermoquad runs with a 1.375" Primary and 2.250" Secondary. The 'big' Thermoquad more than makes up the difference in the Low-Compression, and once the 'Monster-Sized' secondary throttles open up, the light #3165 lb. 'Duster 340' quickly takes off with a 'thunderous' air-grabbing vacuum sound coming from under-the-hood.'

'The Air-Cleaner is an Unsilenced Unit which is a wide-diameter low-profile style, which utilizes an under base-pan trap-door, and a single snorkel air-vent tunnel.'

'Ignition is new for 1972, as Mopar has switched over to Electronic Ignition. Now, the Distributor will utilize a 'Magnetic'
pick-up, and a firewall-mounted ECU {Electronic Control Unit} which will provide for an 'amplified spark'. This will provide
for more spark at higher RPM's and 35% higher voltage to the Spark Plugs.'
 
1972 'Duster 340'

Magazine results........???

With 3.55 Gears
* 4-Speed........ 14.90 @ 92 MPH
* Automatic..... 15.05 @ 91 MPH

This seems more in line.

1972 'Duster 340' with the {very tacky} 'Go-Wing' option.


001.jpg
 
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