340 A body versus 383 B body

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justinp61

justinp61

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There was some discussion in a thread in the small block section about 340 A bodies and 383 B bodies. The information below is a copy and paste from a thread on class racer.

"The below results were from Jerry Gross, Chrysler Technician who tested many Factory Cars.

Tested Average

1968 Barracuda 340-S

* 4-Speed w/3.23 Gears ............. 14.73 @ 96.7 MPH
* Automatic w/3.23 Gears.............14.89 @ 95.1 MPH

* 4-Speed w/3.55 Gears............... 14.44 @ 97.4 MPH
* Automatic w/3.55 Gears............. 14.66 @ 96.8 MPH

1968 383 Road Runner

* 4-Speed w/3.23 Gears............... 15.01 @ 94.2 MPH
* Automatic w/3.23 Gears............. 15.12 @ 93.1 MPH

* 4-Speed w/3.55 Gears............... 14.74 @ 98.0 MPH
* Automatic w/3.55 Gears............. 14.86 @ 95.2 MPH

Remember too, the Barracuda had E70 x 14" Tires, and the Road Runner was equipped with F70 x 14" Tires."
 
A-Body's are always going to be better, less weight. That is the reason that they didn't put 340's in any 68-69 cars except A-Body's. The limiting factory was always the 4" bolt circle and not enough room for bigger tires on Darts, Barracuda's had way more room for them and so did B-body's...
 
A test with 3.91 gears would've been interesting.
 
Looks like the 383 Road Runner likes some gear.
Depends on who did the testing. lol
Motortrend test
68 Barracuda S340 4spd w/3.23 gears 0-60 8.1 sec 15.2 @92 mph
68 Road Runner 383 4spd w/3.23 gears 0-60 6.8 sec 15.0 @93 mph
 
Car Craft test
1970 Dart 340 3spd w/ 3.91 gears 14.7 @ 96.8
 
Those times always seemed slow to me.... Traction? I don't know. But those times just don't stack up from my experiences
 
318willrun said:
Those times always seemed slow to me.... Traction? I don't know. But those times just don't stack up from my experiences
Click to expand...
The times are pretty close no matter who did the testing .
MPH is consistent, so the difference in time is the driver doing the test or traction.
 
fishmens67 said:
The times are pretty close no matter who did the testing .
MPH is consistent, so the difference in time is the driver doing the test or traction.
Click to expand...
My low-dollar 318 ran 14.9's with 2.76's at about 95 mph. Low compression and short block never disassembled. Just a cheapie summit brand cam, stock 318 smog heads that I dremeled, and a 4bbl. I'd say that's a sad day for the "high compression, larger cubes, better heads hot rod engines"... when a X-head 340 and 3.55's can't beat the ET or MPH of a low compression 2.76 geared 318. That's why it seems they are on the slow side.
 
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318willrun said:
My low-dollar 318 ran 14.9's with 2.76's at about 95 mph. Low compression and short block never disassembled. Just a cheapie summit brand cam, stock 318 smog heads that I dremeled, and a 4bbl. I'd say that's a sad day for the "high compression, larger cubes, better heads hot rod engines"... when a X-head 340 and 3.55's can't beat the ET or MPH of a low compression 2.76 geared 318. That's why it seems they are on the slow side.
Click to expand...
On E70 bias tires?
 
justinp61 said:
On E70 bias tires?
Click to expand...
That's why I said above "Traction ??" in post 8. However, means you asked I did it on a normal 205/70R14 and an open rear end with zero traction devices. Also, if you look, the MPH is scary close and the MPH reflects the power. I just think the numbers listed above are low is all.
 
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This is for all the 440 boys that always put the 383 down. lol
Motortrend test
68 Roadrunner 383 4sp w/ 3.23 gear 15.0 @ 93mph
68 Dodge Cornet RT 375 HP 440 4spd w/ 3.54 gear 15.10 @94 mph :lol:
 
fishmens67 said:
This is for all the 440 boys that always put the 383 down. lol
Motortrend test
68 Roadrunner 383 4sp w/ 3.23 gear 15.0 @ 93mph
68 Dodge Cornet RT 375 HP 440 4spd w/ 3.54 gear 15.10 @94 mph :lol:
Click to expand...
Do you believe yourself that that's all the HP 440 with 3.54's could turn, 94 mph?
 
318willrun said:
Do you believe yourself that that's all the HP 440 with 3.54's could turn, 94 mph?
Click to expand...
No, I was just showing a test for a certain day. lol
actually in reality the 440 RT runs about 100 mph in the 1/4
 
All and all the tests show how good the 340 and 383 ran considering p/w ratio. pretty close.
 
Don't take these 60’s drag test as gospel. These test cars were brand new with a few hundred miles, tight engines and rear ends with bias ply tires. Lots of rolling resistance.

The 205 radials, modern cam, ported heads make a big difference on the 318. And so does the density altitude and water grains. Anyone who races k
already knows this. The magazines seldom talk about what track and what the weather was that day.

the early cars were made in august and if they were drag testing in august or September the air could be bad for making power.
 
I remember a magazine test with a 4-speed car one month, then the next month they had Ronnie Sox drive the same car, it was WAY quicker and faster...
 
HemiSSDart said:
I remember a magazine test with a 4-speed car one month, then the next month they had Ronnie Sox drive the same car, it was WAY quicker and faster...
Click to expand...
He was probably the driver for all the tests. lol
Consistency and the same rear axle ratio usually benefits the automatic.
 
HemiSSDart said:
I remember a magazine test with a 4-speed car one month, then the next month they had Ronnie Sox drive the same car, it was WAY quicker and faster...
Click to expand...
If it’s the same test I saw it was a 440-6 B body.
 
8.1 0-60 for the 340S? Someone had no idea how to drive.

Stock 440 and Hemi cars will mudhole a 383, simple as that.

The hemi vs 440 test was almost exactly like my stuff ran comparatively. 440 would get out early, then the Hemi would start spanking it around 500 feet out.
 
Those #s are about what you would expect for production engines, engine size & car weight.

American supercars, Roger Huntington, with estimated hp:
- 68 GTX, 440, auto, 3.23, 375 hp [ est 330 ] 14.6 @ 96.
- 69 Dodge R/T, 440 6 pack, 3.91, auto, 14.2 @ 100, 390 hp [ 370 ]
- 68 Barra 340, 3.23, auto, 14.6 @ 96 275 hp [ 290 hp.] Note: est HP higher than quoted HP.
- 70AAR 340 6V Cuda, 3.55, M4, 14.5 @ 99, 290 hp [ 310 ]
 
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