72 340 build vs...other options

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AJ/FormS said:
How many old Mopars have you owned? and how many of those were NOT 318s?
The bores range from 3.91 to 4.04, a range of 3.3%
The strokes range from 3.315 to 3.58 a range of 8%.
the sizes have a range of 13.2%
For your application;
Case closed.

On the street, with an A-body;
you do not need 2.02s
you do not need a long stroke
You do not need forged parts
Any top end will fit on any bottom end.
Allowing for cylinder-pressure adjustments;
A 318 with a cam one size bigger than a 340, will match it for power.
A 318 with max compression will match the bottom end of a stock 360.
A lo-compression 340 with a 318 cam will about match the 318 for fuel economy but have more bottom end.
The 340 burble was more from the rectangular tips and high-energy exhaust. The 44* of overlap is actually very modest. For the street, I don't think much of the 340 cam and I have several of them packed away.
A 318 will happily rev to whatever a 340 can, and so will a 360. All any of them need is the right springs and lifters. KB107 pistons for the 360 are about 2/3rd the weight of the 340 forged slugs. After balancing, the 360 crank will go to 7200 as often as you like for more than 125,000 miles (mine)
A 360 can happily pull 65=1600 rpm (mine) all day every day. Try that with your 340.
What the 360 can do with a 3-gear manual, a 340 will need 4 gears, and the 318 will like 5
If a city car; the rear gears will need to be a least 10% greater between each engine. What the 360 can do with 2.94s, the 340 will need 3.23s and the 318 needs 3.55s.. As the engines get smaller, Second gear becomes very important, so that you always have the right amount of torque on tap.
_______________________________________________
From Experience, I can tell you that having 400 ftlbs on tap at 45 mph is seriously big fun, but 400 ftlbs at 90 mph is nothing to write home about and 400 at zero-mph is absolutely bonkers
You cannot get 400 out of a streetable normally aspirated 318
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Amen!

Hero post of facts! AJ killed it.
 
Same crank spacers. 360 block @ .030 over, MP forged slugs for the MP forged 3.45 crank, Eagle forged rods. 352 cubic inches.

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Dartswinger70 said:
So since the 318 guys never want to have a civil discussion
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This is not 100% true but this thread is about you loosssing your cool and assuming as well as misreading and showing a lack of comprehension. Get over it.
Dartswinger70 said:
about anything other than converting a 318 into a race engine
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That was not the thread topic nor was it a actual route taken, however, it was a joke that was made.
Dartswinger70 said:
I got to thinking, how does the 72-73 340 stack up say as compared to a 360. If I was an aspiring small block Mopar guy
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360, readily available as a 5.9, cheap, 3.58 stroke is good for low speed power while high reving is EZ.
Dartswinger70 said:
graduating from the depths of 318dom into something with a few more cubes, is it wise to pick up a 72 340 or opt for a 5.9/360 type build. I saw a Nicks Garage video where Nick ran a 72 340 with a Thermoquad and got 300-335 horse. Its interesting what these later 340s put out in actual numbers. Lets have a nice chat and... its a 340 thread :thumbsup:
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The later 340’s lack compression. That’s it really.

Dartswinger70 said:
P.S. Ill list what I like about the later 340.
1. the heads - its a 360 casting but can have 2.02s put in fairly easy
2. the block -no matter how you slice it its a 340 block you can do whatever with it that you could do with the earlier block Id think swapping pistons would be on my mind.
3. The crank - depending on build date you may have a forged crank good for high rpm.
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I turned my cast crank 6800 for years. No issues. Not even with the cast pistons.
Dartswinger70 said:
4. Pistons - even the later ones had valve releifs - can use high lift cam
5. That 72 Thermoquad setup right down to the trap door air cleaner- I don't know, it just worked...
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Love that set up. Using it now.
Dartswinger70 said:
What I dont like about later 340:

1. The heads - the J with the bigger combustion chambers, combined with the low comp pistons BUT that can be overcome with earlier style pistons.
2. The internal vs external balance forged vs cast crank by build date
3. it was getting to be the smog era.
4. the 8.5:1 compression ratio

My conclusion is I wouldn't sneeze at a later 340 yeah I know some are external balance but so is the 360 that's easy to over come and live with..

All things considered this engine is fairly easier to straight up mod into a strip screamer than a 318- just swap in parts from the 68-71 340
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Let’s run through that parts list one by one and compare!
Dartswinger70 said:
I saw a later 340 on here recently for 1500-1600 dollars to me that's a deal and a good starting point for a build. OR would you go 360?
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$1,600 goes a lot further in a 360 than a 330 that needs a rebuild and purchased at $1,600. If I had both engines already on a stand, for me it would depend on what I’m doing with the engine as to which I’m building.
Dartswinger70 said:
see how easy that is? yeah I know "340s aren't available" but I see them on here regularly. Ante up...you are paying for convenience and performance.

What say you?
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Anti up $1,600 for an entrance fee on an engine that needs to be rebuilt?
 
If given the choice between a 318, 340, and a 360, as a starting point. Pretty much everyone would pick the 340.

In addition to the displacement advantage, let's not ignore the valve deshrouding advantage offered by the larger bore.

Building a basic street motor? It's splitting hairs. Trying to build something serious, especially NA? These things add up.

I hear the 372 is an excellent all around combo.
 
Dartswinger70 said:
So since the 318 guys never want to have a civil discussion about anything other than converting a 318 into a race engine I got to thinking, how does the 72-73 340 stack up say as compared to a 360. If I was an aspiring small block Mopar guy

graduating from the depths of 318dom into something with a few more cubes, is it wise to pick up a 72 340 or opt for a 5.9/360 type build. I saw a Nicks Garage video where Nick ran a 72 340 with a Thermoquad and got 300-335 horse. Its interesting what these later 340s put out in actual numbers. Lets have a nice chat and... its a 340 thread :thumbsup:

P.S. Ill list what I like about the later 340.
1. the heads - its a 360 casting but can have 2.02s put in fairly easy
2. the block -no matter how you slice it its a 340 block you can do whatever with it that you could do with the earlier block Id think swapping pistons would be on my mind.
3. The crank - depending on build date you may have a forged crank good for high rpm.
4. Pistons - even the later ones had valve releifs - can use high lift cam
5. That 72 Thermoquad setup right down to the trap door air cleaner- I don't know, it just worked...

What I dont like about later 340:

1. The heads - the J with the bigger combustion chambers, combined with the low comp pistons BUT that can be overcome with earlier style pistons.
2. The internal vs external balance forged vs cast crank by build date
3. it was getting to be the smog era.
4. the 8.5:1 compression ratio

My conclusion is I wouldn't sneeze at a later 340 yeah I know some are external balance but so is the 360 that's easy to over come and live with..

All things considered this engine is fairly easier to straight up mod into a strip screamer than a 318- just swap in parts from the 68-71 340

I saw a later 340 on here recently for 1500-1600 dollars to me that's a deal and a good starting point for a build. OR would you go 360?

see how easy that is? yeah I know "340s aren't available" but I see them on here regularly. Ante up...you are paying for convenience and performance.

What say you?
Click to expand...
that 72 340 nick tested wasnt even close to stock
 
rumblefish360 said:
This is not 100% true but this thread is about you loosssing your cool and assuming as well as misreading and showing a lack of comprehension. Get over it.

That was not the thread topic nor was it a actual route taken, however, it was a joke that was made.

360, readily available as a 5.9, cheap, 3.58 stroke is good for low speed power while high reving is EZ.


The later 340’s lack compression. That’s it really.


I turned my cast crank 6800 for years. No issues. Not even with the cast pistons.

Love that set up. Using it now.

Let’s run through that parts list one by one and compare!


$1,600 goes a lot further in a 360 than a 330 that needs a rebuild and purchased at $1,600. If I had both engines already on a stand, for me it would depend on what I’m doing with the engine as to which I’m building.


Anti up $1,600 for an entrance fee on an engine that needs to be rebuilt?
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Lemme gat this straight I leave the thread where you are ganging up on me for the ONLY reason being you don't like me ( which I could care less) and start my own thread and you come in here to start your crap. PM me and we can make other arrangements if you have some problem to settle here dont continue on with your BS...this is exactly why Repliracer isnt here anymore you people are biased, rude, lack any sense of humour and are authoritative and cliquey plus you carry grudges ...you have an issue with me I'm not concerned you'll be on ignore or like Repliracer I'll leave ...I'm not here argue with you nitwits...
 
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a-bodyguy said:
that 72 340 nick tested wasnt even close to stock
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Well, dont leave us hanging, please list what modifications were done. I did see he did a pull with a Thermoquad which oh, lemme see I'm sure was stock in 72 with that what do you call it? trap door air cleaner...Yeah that setup sure looked stock to me please elaborate....that's why were here right ?
 
Dartswinger70 said:
Well, dont leave us hanging, please list what modifications were done. I did see he did a pull with a Thermoquad which oh, lemme see I'm sure was stock in 72 with that what do you call it? trap door air cleaner...Yeah that setup sure looked stock to me please elaborate....that's why were here right ?
Click to expand...
nhra factors motors based on weight and trap mph hard to argue that
the best 340 is rated 320 or 325 not going to look it up that is 71 340 with the t/quad
we all know it was luck of the draw on cc of the heads smaller more comp more power
the other non smog 340 ratings are 310 hp and 295hp
the chit carter carb makes 20 hp less then the t/quad
seems this should all be known by 340 a-body people
the 68 340 manual cam smallest cc chambers and t/quad would be the best period
72 340 is 8.5to 1 thats 2 advertised points lower then 10.5 and 10.2 to 1
if the good 340 are lower 9.5 big cc maybe the 72 340 is 8 to 1
bottom line its not making 10 hp more then the highest rated fastest nhra stock class rated 340
common sense
 
Dartswinger70 said:
Well, dont leave us hanging, please list what modifications were done. I did see he did a pull with a Thermoquad which oh, lemme see I'm sure was stock in 72 with that what do you call it? trap door air cleaner...Yeah that setup sure looked stock to me please elaborate....that's why were here right ?
Click to expand...
just watched the vid again saw that a few days ago
379 lb feet torque@4300 stock was 3400 rpm
350 hp@5500
vacuum was 13.7@800 rpm idle
clearly not a stock cam
carb is 750 avs
lost power with t/quad it needed tunning
no alternator
electric water pump
 
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Mean416 said:
If given the choice between a 318, 340, and a 360, as a starting point. Pretty much everyone would pick the 340.

In addition to the displacement advantage, let's not ignore the valve deshrouding advantage offered by the larger bore.

Building a basic street motor? It's splitting hairs. Trying to build something serious, especially NA? These things add up.

I hear the 372 is an excellent all around combo.
Click to expand...
Ahhhhh, a 372, that’s in line in the garage.
 
a-bodyguy said:
nhra factors motors based on weight and trap mph hard to argue that
the best 340 is rated 320 or 325 not going to look it up that is 71 340 with the t/quad
we all know it was luck of the draw on cc of the heads smaller more comp more power
the other non smog 340 ratings are 310 hp and 295hp
the chit carter carb makes 20 hp less then the t/quad
seems this should all be known by 340 a-body people
the 68 340 manual cam smallest cc chambers and t/quad would be the best period
72 340 is 8.5to 1 thats 2 advertised points lower then 10.5 and 10.2 to 1
if the good 340 are lower 9.5 big cc maybe the 72 340 is 8 to 1
bottom line its not making 10 hp more then the highest rated fastest nhra stock
Click to expand...

a-bodyguy said:
just watched the vid again saw that a few days ago
379 lb feet torque@4300 stock was 3400 rpm
350 hp@5500
vacuum was 13.7@800 rpm idle
clearly not a stock cam
carb is 750 avs
lost power with t/quad it needed tunning
no alternator
electric water pump
Click to expand...
thanks for clarifying on that.
 
Dartswinger70 said:
Lemme gat this straight
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Oh, something you should have tried in the other thread. But OK, here we go!
Dartswinger70 said:
I leave the thread where you are ganging up on me
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Stop, I replied to your replies. Besides, how can 1 person gang up on someone. All I did was nearly correct the wrong things you said and called into question your claims where you mistook them, assumed and twisted my words, lied and gave parting shots and insults before I insulted you back which you there by went off the hook freaking out like a little girl, a label you earned and deserved.

Next….
Dartswinger70 said:
for the ONLY reason being you don't like me
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Incorrect!
Dartswinger70 said:
(which I could care less)
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Good for you!
Dartswinger70 said:
and start my own thread and you come in here to start your crap.
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Nope, not really, just sayin.
Dartswinger70 said:
PM me and we can make other arrangements
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Sorry, a dinner date is out.
Dartswinger70 said:
if you have some problem to settle here
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Nope
Dartswinger70 said:
dont continue on with your BS..
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Stopping your BS of incorrect information
Dartswinger70 said:
.this is exactly why Repliracer isnt here anymore
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Incorrect. I speak with him every once in a while. An excellent guy. His issue is not what I was doing but how you feel.
But you won’t get that until later, possibly…
Your comprehension level is low so I’ll try to dumb it down for you and make it easy.
Dartswinger70 said:
you people are biased, rude, lack any sense of humour and are authoritative and cliquey plus you carry grudges ..
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And yet you started the BS, please re. Heck the thread and see what you said first before you point to what I said. Then you might be starting to get a clue.
Dartswinger70 said:
.you have an issue with me
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O my when you post wrong information
Dartswinger70 said:
I'm not concerned you'll be on ignore or like Repliracer I'll leave ...I'm not here argue with you nitwits...
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Your the nitwit but haven’t figured it out yet.
Dartswinger70 said:
I've owned 3 is that not enough or do I need a farm field full of rusted junk cars to be a MOPAR enthisiast...first was a slant second a 318 last a 340 car...
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IDGAF how many of what ever you owned. You can be a MoPar enthusiast without owning a single one.
 
273 said:
Did you have to align hone it?
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No sir, it did not need it. The block has dyno time only coming from a big shop.
273 said:
I got a 0.040" 360 with a spun rod, wouldn't mind making into a poor mans 340.
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The problem is getting a 340/3.31 stroke crank into the larger journal of the 360. As Newbomb Turk stated, he called up Bill and there not being made anymore. Dang shame.
 
rumblefish360 said:
Oh, something you should have tried in the other thread. But OK, here we go!

Stop, I replied to your replies. Besides, how can 1 person gang up on someone. All I did was nearly correct the wrong things you said and called into question your claims where you mistook them, assumed and twisted my words, lied and gave parting shots and insults before I insulted you back which you there by went off the hook freaking out like a little girl, a label you earned and deserved.

Next….

Incorrect!

Good for you!

Nope, not really, just sayin.

Sorry, a dinner date is out.

Nope

Stopping your BS of incorrect information

Incorrect. I speak with him every once in a while. An excellent guy. His issue is not what I was doing but how you feel.
But you won’t get that until later, possibly…
Your comprehension level is low so I’ll try to dumb it down for you and make it easy.

And yet you started the BS, please re. Heck the thread and see what you said first before you point to what I said. Then you might be starting to get a clue.

O my when you post wrong information

Your the nitwit but haven’t figured it out yet.

IDGAF how many of what ever you owned. You can be a MoPar enthusiast without owning a single on
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I'm pretty sure I've had about enough of you now...I'm putting you on ignore because I'm not interested in anything you have to say, but by all means continue to correct me on my posts :lol:
 
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junkyardhero said:
oohhhh! did you guys hear? there's gonna be a fight after school under the bleachers!

be there or be square!
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I admit, I’m square!

LMAO

Dartswinger70 said:
I'm pretty sure I've had about enough of you now...I'm putting you on ignore because I'm not interested in anything you have to say, but by all means continue to correct me on my posts
Click to expand...

At least you had a laughing smiley face on the end of that one.
Perhaps I will!
Enjoy!
 
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