Did the 340 really make 275hp?

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DusterKrazy said:
I'm pretty sure the '71 had an 850??
BTW, Can anyone speak out on '71 vs. '72 340 performance (as in seat of the pants power?)
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My best friend Rick (RIP) ordered a new 72 340 Duster, 4 speed with 3.23 SG. As soon as Spring came we went to the track. (April 72?) The ONLY change from stock was G70x14 Polyglas on the back. It ran 14.51 in the quarter.

I still say a 71 340 A-body with factory 3.91 gears (if available) and a 4 speed would be the fastest Mopar small block ever built, pure stock. The 340's like a bigger carb than usual and the 71 TQ was it. I wish I knew what a STOCK 68 340 4 speed, 3.91 cuda coupe would do.
 
Thanks for the input. A local guy has a '68 Barracuda notchback with it's stock 340/auto. It WILL SCREAM and has been a regular class winner here.
 
Remember though, it's not just the powerplant. It's the entire combination. The 340 in our beloved A bodies has always been one of the most feared and legendary combinations ever made by any auto maker.
 

StrokerScamp said:
Remember though, it's not just the powerplant. It's the entire combination. The 340 in our beloved A bodies has always been one of the most feared and legendary combinations ever made by any auto maker.
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Agreed

Some of my older customers (remember, I'm in my 20's) ask what's under the hood of my '74 and when I say "340" they shake their head and sigh "You're insane, kid" :D
 
74Dusted said:
Agreed

Some of my older customers (remember, I'm in my 20's) ask what's under the hood of my '74 and when I say "340" they shake their head and sigh "You're insane, kid" :D
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They're saying "You're insane" because no 1974 340's were ever built. 1973 was the last year for the 340.

It was replaced in 1974 by the longer stroke (but smaller bore) 360, which had the same heads and intake system as the '73 340, but lots more torque due to the stroke increase (and 20 extra cubic inches.)

I think the cams were the same.

The (higher) early 340 compression ratio gave that engine more snap, but the 360 was probably a better street engine for the heavier 1974-'76 A bodies, delivering more torque for daily driving. The one-year-only '68 stick shift cam was also a plus, but was gone from the lineup all-too-soon.

I think that a '68 340 Dart (shipping wt. 3,038,) with a 4-speed manual transmission would be a really close race for a '71 Duster 340 4-speed (shipping wt. 3,140.) The better cam and lighter weight in the '68 might offset the bigger carb on the '71.
 
Bill Dedman said:
They're saying "You're insane" because no 1974 340's were ever built. 1973 was the last year for the 340.

It was replaced in 1974 by the longer stroke (but smaller bore) 360, which had the same heads and intake system as the '73 340, but lots more torque due to the stroke increase (and 20 extra cubic inches.)

I think the cams were the same.

The (higher) early 340 compression ratio gave that engine more snap, but the 360 was probably a better street engine for the heavier 1974-'76 A bodies, delivering more torque for daily driving. The one-year-only '68 stick shift cam was also a plus, but was gone from the lineup all-too-soon.

I think that a '68 340 Dart (shipping wt. 3,038,) with a 4-speed manual transmission would be a really close race for a '71 Duster 340 4-speed (shipping wt. 3,140.) The better cam and lighter weight in the '68 might offset the bigger carb on the '71.
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Oh they know it wasn't a 340 car originally (still have the original 318 on an engine stand in the corner of the garage) It's got a '70 340 in it (with a LD340 intake & an 850 TQ), along with '71 bumpers, no carpet padding, no spare tire, no bumper jack, lighter bucket seats and whatever else I could remove from the car without losing creature comforts.

And in about 2 weeks (when it arrives) it'll have a 6-71 blower on it :D
 
Once again folks. Horse power was calculated differant, '71 and back than '72 forward. 340's were rated at 275 hp, and much underated at the time, but overated by today's formulas.
 
74Dusted said:
Oh they know it wasn't a 340 car originally (still have the original 318 on an engine stand in the corner of the garage) It's got a '70 340 in it (with a LD340 intake & an 850 TQ), along with '71 bumpers, no carpet padding, no spare tire, no bumper jack, lighter bucket seats and whatever else I could remove from the car without losing creature comforts.

And in about 2 weeks (when it arrives) it'll have a 6-71 blower on it :D
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good for you, great example of a young gun keeping it going. good for you man:thumrigh:
 
74Dusted said:
Oh they know it wasn't a 340 car originally (still have the original 318 on an engine stand in the corner of the garage) It's got a '70 340 in it (with a LD340 intake & an 850 TQ), along with '71 bumpers, no carpet padding, no spare tire, no bumper jack, lighter bucket seats and whatever else I could remove from the car without losing creature comforts.

And in about 2 weeks (when it arrives) it'll have a 6-71 blower on it :D
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Sounds like you know how to have fun with a car!!!

Congratulations; most guys your age don't know which end of a spark plug to screw into a motor. LOL!

Keep us updated on the blower project!:cheers:
 
Bill Dedman said:
Sounds like you know how to have fun with a car!!!

Congratulations; most guys your age don't know which end of a spark plug to screw into a motor. LOL!

Keep us updated on the blower project!:cheers:
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My best friend was one of those guys until about a month ago. He started hanging around the garage when I was working on my Duster and it all went downhill from there :D. He has a Mazda RX-7 (1.3L rotary) and wanted an "In your face' performance increase... So I'm going to build up a mild Blown 318 (with some help from him) for his car, while at the same time putting together my Blown 340.
 
74Dusted said:
My best friend was one of those guys until about a month ago. He started hanging around the garage when I was working on my Duster and it all went downhill from there :D. He has a Mazda RX-7 (1.3L rotary) and wanted an "In your face' performance increase... So I'm going to build up a mild Blown 318 (with some help from him) for his car, while at the same time putting together my Blown 340.
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Sounds like he might should investigate turbocharging that rotary with a significant amount of boost. Might be cheaper than building a 318 and swapping, which will upset the balance of the car. I'd imagine that a 318 is considerably heavier than a rotary, even with aluminum heads.

I think rotarys like turbocharging; the factory even did it for them until a few years ago, but I think they were low-boost applications.

I once saw a Super Eliminator (7,99 index) dragster with a super (not turbo) charged rotary that was SO LOUD that the big block Chebbys in the other lane couldn't hear their engines. LOL!
He broke out, running a 7.66... Powerful car!
 
He had been considering the Turbo route, but wanted something 'different' and when he heard about how people were putting SBC and SBF engines in those little cars, he asked me if we could put a mopar engine in his :D

I know of one RX-7 running a 440/727 :prayer: No need to go that insane for a mild v8 conversion, I bet that thing throws sparks every time it hits a bump :D :oops:
 
I always wondered how they could rate a 327 @ 375 H.P. and then rate the '70 340 @ 275 H.P......or at least not rate it @ 1 H.P. per cube. The 340 on paper looks more impressive compared to those older chevy motors, and the chevy motors definitely didn't have any great looking exhaust manifolding either. Interesting.....but I also think the proof is in the quarter-mile times too. Maybe 340's have a flatter torque curve.
 
true story...I raced a 65 vet after a local cruz he had a fresh fuel injected 330 against my m1 292/510 themo xhead 345 I pulled him in every gear beat him by at least 3 car lengths that felt good!! another one bites the dust
 
Put a 327/375hp, .490 lift, 250 @ .050 solid cam in a 340 along with a holley carb instead of an AVS and see what it makes. Compare camshafts from the hot chevy engines, big and small, to the mopars. Basically no solid cams in 66+ mopars, sans 66-69 Hemis. The mopars are dinky in comparison, even the Hemi stick is REALLY light.

The wide TQ curve is what made mopars run. Not peaky like the Chevy stuff.
 
Bill deadman is dead on about the rotary. It makes monster power,and is very compact/light. If I had one I wouln't replace it with a 318 unless I was going strictly drag racing. Then it would be a cage car,lol...be real fast and lite!
 
Bill Dedman said:
I'll bet you're right!

If he's considering a 318, he might as well install a 360; insignicant difference in weight, and an extra 42 cubes...

Just sayin'...:cheers:
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The 318 was practically free, and came with a 727 bolted to it. Once the car is set up for the small block (like my dodge d50) it's a simple task to upgrade to a 340/360/Stroker since the small block mounts/wiring/etc are already in place.


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needsaresto, you're right about the rotary, they are a good engine. Also very expensive to play with (more than our small blocks)

He's on the College & Working Man's performance budget. I totally respect that, because I've been there. And when he finally gets his recording studio up and running, we can drop in a 20B (or is it 23B?) 4-Rotor Turbo engine instead of the 13B we're taking out to put in the Blown 318.
 
74Dusted said:
The 318 was practically free, and came with a 727 bolted to it. QUOTE]

Can't beat a deal like that!:cheers:

Like I said, you seem to know how to have a good time with cars!!!

Maybe he can swap that 727 for a 904, and pick up about a car-length and a half in the process... If he's gonna race it, that's a worthwhile improvement.
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