340 block value?

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Well that's all about as interesting as I thought it might be. It would be sensible to assume someone with the background of Jim Szilagyi (Mopar Motorsports small block Mopar race parts developer) should have the facts down, but I think we all know facts can be hard to pin down. Regardless I'm finding his book to be a very valuable and enjoyable read.
I do think I'd rather sonic test my engine block than the block on top of my shoulders :)
I'd get the number off the block but its not so easy to get at where its stored.
It's going to sit where its at since there's a small chance I may restore the car it came from.
Thanks for all the interesting conversation.
 
yes blocks are sand castings. to my knowledge they do not use a permanent mold where it is reused. sand mixed with oil is rammed up over a pattern or a match plate in this case as it is a high production item in a 2 flasks. the flasks are separated, the match plate is removed and in its place is a core for the water jacket. both flasks are put back together and filled with molten iron. after cooling, the sand is broken away. so the first one out of the mold is bs.
 
FWIW, for those who want to sonic test their own blocks, I have found and use a decent and (relatively) affordable sonic tester; look up TM-8812.

You carefully have to file off some material either side of the transducer gap running down the middle of the test head (being very careful to never touch the gap itself with the file) to make it conform to a round cylinder. But one that is done, you are in business. Adjust the velocity factor to get the right thickness readings on a piece of cast iron that you can directly measure (like a cast brake rotor). I have measured wall thicknesses with this tool and then double-checked the thickness with mechanical means and it is accurate within a few thousandths.

Simple white lithium grease works 100% fine as a sonic media between the sonic tester head and the material under test.

BTW, you guys would freak over the wall thickness of Opel 1.9L blocks.... .300" on the major and minor thrust faces is the average LOL. Plus an unsupported bore wall length of under 5".... overbore heaven!
 
A56 said:
I checked mymopar.com and they only show LA 360 from 71-74 casting # 3418496, 75-78 casting #3870230 and 75-93 casting # 4179930. What is your casting number?
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Looks like a 496 casting, so nothing special, just a early block.
I remember it had plenty of wall thickness.

83FFD7FD-1955-4869-84EE-C55BAC4DF138.jpeg


C36F0C0A-EEAE-47AF-8EC6-8514A25B98AE.jpeg
 
I would be hard pressed to sell a 340 block for less than 7-8 hundred
Getting harder to find in good shape.
A decent 360 block that’s clean and can be proven ready to go, as in sonic test and at standard bore. I would think is 4-5 hundred with mains and bolts.
That stuff will be gold one day. Maybe silver.
 
12swinger said:
I would be hard pressed to sell a 340 block for less than 7-8 hundred
Getting harder to find in good shape.
A decent 360 block that’s clean and can be proven ready to go, as in sonic test and at standard bore. I would think is 4-5 hundred with mains and bolts.
That stuff will be gold one day. Maybe silver.
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Depends a lot on where you live. I can get good condition running 5.9L's pulled for $400-500 around here. Bought a .030 over 360 blocks with caps for $50.
 
Idaho said:
In my research for building a 5.9 into a 408 stroker, I read that the 340 is a preferred production engine for a stroker build due to its large bore and thick walls that can take a .040 overbore to make a 418 stroker.

This reference (How to Build Big-Inch Mopar Small Blocks) suggests that although its common to bore 0.030 over, the 5.9 should really only be bored to .020 over to avoid thin walls and distortion. Seems a little silly all the stroker kits advertised are at .030 over.

I happen to have a 340 from a 73 Duster, uncertain miles, but running when pulled. I don't plan to use it as I have a lot of parts for the 5.9 already that don't transfer over. So I'm curious regarding its value. I may consider having it tanked and magnafluxed if there's enough value there. I'm assuming the rest of the engine has no real value given that the 73 340 used a cast crank (shot peened IIRC).

A quick check on EBAY turned up a single very rusty 340 block for $900. Course he might be dreaming.
Click to expand...

Dreaming.
This why most will only pay around 400.00 for an old 340 block.
dodge/mopar 340 engine - auto parts - by owner - vehicle automotive...

Rusted and total mystery , add is misleading saying it was machined, wrong heads for the yr...and revision #8

How about this gem, imagine spending 35 to find out you have nothing but a core.
Two Mopar 340 long block engines - auto parts - by owner - vehicle...

Scammers.
When it comes down to it ..the parts that go into one of these blocks ..they are way more money than the block is worth...then add to machining.
Imagine buying an over priced pos that needs 3 sleeves, a line hone, bore n hone, square deck. $$$$

How much is a race block again? Lol
Cause if anyone was to pay a going rate of 900 for a old 340 block... by the time its full boogie at the shop... you're under water.
 
yellow rose said:
Love that pan.
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Yeah it’s the only solution for a bad design issue, so we can have a rear sump.
I ended up with 2 of these for the 340/318 and I bought one new for the 360 about a decade ago.
I assume originally it was intended to use the taller oil pump gears, and use of the pump cover that came with this setup.
I machined the cover flat and used the hv pump, bolted it direct to pump.
Seems to work good.
I never had the swinging pickup that was intended to be used.
 
12swinger said:
Yeah it’s the only solution for a bad design issue, so we can have a rear sump.
I ended up with 2 of these for the 340/318 and I bought one new for the 360 about a decade ago.
I assume originally it was intended to use the taller oil pump gears, and use of the pump cover that came with this setup.
I machined the cover flat and used the hv pump, bolted it direct to pump.
Seems to work good.
I never had the swinging pickup that was intended to be used.
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They actually made a static pickup as well. That's what I'm using in my current engine. The new engine will have the swinging pickup.

LOL I had the older cover that allowed you to use the HV gears in the standard volume housing. I did the same thing. Machined it flat and bolted it on.

I wish the still made that pan and pickup.
 
yellow rose said:
They actually made a static pickup as well. That's what I'm using in my current engine. The new engine will have the swinging pickup.

LOL I had the older cover that allowed you to use the HV gears in the standard volume housing. I did the same thing. Machined it flat and bolted it on.

I wish the still made that pan and pickup.
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It must hold up I suppose.
I was a little concerned at first, as the gear now runs against the aluminum pump cover, instead of the iron cover.
 
12swinger said:
It must hold up I suppose.
I was a little concerned at first, as the gear now runs against the aluminum pump cover, instead of the iron cover.
Click to expand...


I haven't had any issues. Really, there shouldn't be any downward load against the gears. The shoulder of the pump drive should stop on the shoulder of the intermediate bushing.

The only way I could see it might be an issue is if the pump drive was long enough to bottom out in the pump.
 
72bluNblu said:
Most of that is old wives tails. Most of the LA engines will take a .060” overbore, 360’s included. I’ve heard of 318’s going .090” over. Like everything else made back then there were tolerances so on any LA block it’s good practice to have a sonic check done if you’re going much past .030”, core shift happens and there are blocks that won’t go .060”. The ‘68 340 in my Duster is .060” over and works great.

As for the 5.9’s, I wouldn’t be surprised if they were a little more “economic” with their wall thickness. But probably more consistent too. I have heard the .020” over limit before, but I don’t have one so I never bothered to investigate further.

The 340 blocks do get a little more money, just a nostalgia thing mostly. I’ve seen them go for a few hundred bucks all the way up to a thousand. Depends on condition and the current bore diameter. I assume some of the earlier ones go for more because there are probably folks out there looking for date code or even matching number blocks for some of the more valuable 340 cars.




Funny, I’d heard to look for early castings but not “1”. Reason being it usually took a couple modifications to the mold for them to get things sorted out. So like a “3” would be great. Obviously by the higher numbers the mold might be getting used up and those wouldn’t be great either.
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That is close, the number after the dash is the ‘mold number’
Typically v8 blocks were molded two at a time so the first set would be mold 1 and mold 2. The next set would be molds 3 & 4 and so forth.
There could be some truth thinking that higher numbered molds could be more accurate than lower numbered molds in that changes and fixes could be incorporated into the newer molds from issues resolved.
The molds are replaced as the molding sand process is very abrasive to the mold form, even though the surface of the mold is hard chrome plated.
But the molds are used for many cycles, perhaps 100000 or so before they would need a major overhaul.
Also the advice on sonic testing is ‘right on’. Foundry and machining processes improved over time but there was always variation in the results.
 
nm9stheham said:
FWIW, for those who want to sonic test their own blocks, I have found and use a decent and (relatively) affordable sonic tester; look up TM-8812.

You carefully have to file off some material either side of the transducer gap running down the middle of the test head (being very careful to never touch the gap itself with the file) to make it conform to a round cylinder. But one that is done, you are in business. Adjust the velocity factor to get the right thickness readings on a piece of cast iron that you can directly measure (like a cast brake rotor). I have measured wall thicknesses with this tool and then double-checked the thickness with mechanical means and it is accurate within a few thousandths.

Simple white lithium grease works 100% fine as a sonic media between the sonic tester head and the material under test.

BTW, you guys would freak over the wall thickness of Opel 1.9L blocks.... .300" on the major and minor thrust faces is the average LOL. Plus an unsupported bore wall length of under 5".... overbore heaven!
Click to expand...

Cool. I'm always impressed with the things people on here figure out.
 
12swinger said:
It must hold up I suppose.
I was a little concerned at first, as the gear now runs against the aluminum pump cover, instead of the iron cover.
Click to expand...
I've got an engine that only ever had an aluminum cover with a twin gear pump design (and an AL housing). Not any issues besides normal pump wear (from crap out of the pan), and the downward thrust on the shaft is taken by the bushing, like YR sez.
 
Something no one has yet mentioned: 340 main bearing diameters are smaller than 360. Less bearing friction, but also less rigid crank. Whether it's enough difference to worry about either way, I don't know.
 
But also more leverage on the 360 crank from the longer throws... I guess that's what drove the larger main journal size.
 
nm9stheham said:
But also more leverage on the 360 crank from the longer throws... I guess that's what drove the larger main journal size.
Click to expand...


The larger main journals was to increase the Rod throw overlap because the crank was cast steel and not forged steel.

That's why all the Buick, Olds and Pontiac stuff had comparatively large main diameters. They all had fairly long strokes and cast cranks.
 
65 Cuda 340 said:
Something no one has yet mentioned: 340 main bearing diameters are smaller than 360. Less bearing friction, but also less rigid crank. Whether it's enough difference to worry about either way, I don't know.
Click to expand...

I worry less about the crank flexing than I do the block moving all over the place, and the bigger hole in the block let's it move more.
 
C498DF1D-3F5C-4BCC-A7E1-20CFA468B044.jpeg
nm9stheham said:
I've got an engine that only ever had an aluminum cover with a twin gear pump design (and an AL housing). Not any issues besides normal pump wear (from crap out of the pan), and the downward thrust on the shaft is taken by the bushing, like YR sez.
Click to expand...
It’s together
 
rumblefish360 said:
Is that Milodon kit still available?
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Don't I wish. I happen to have one in the car and one ready for the new engine.

They are hard to find. The one for the new engine will have the swinging pick up.

Shame on you Milodon for discontinuing this pan and pick up system.
 
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