Stop discarding good 340 engines ! !

[Inertia]

I'm concerned perfectly good 340s are being thrown out ! !
In the last coupla weeks there have been posts about not using a 340 block bored over .030 .
ManufacturerS tooled up to produce .060 pistons, and wouldn't have done so without research, and a huge market. Save those 340s !

Here's a paragraph from the Mopar Performance Engine Manual .

If you insist on being rid of it/them, send them to me, I'll use them . tia .

 

[bigfoot]

Even if it was thin after .030 it could be sleeved, who throws this stuff away? Good lord.

 

[Mtrhead]

I have many 30 over blocks and I get $1,200 a piece

 

[Mtrhead]

They love 340s here in the south

 

[dano]

I think a good rule of thumb for any block is get it sonic checked before hand. It isn't cheap to rebuild an engine anymore (unless you own you're own shop with all the capabilities to do so) so why not have the peace of mind for a good foundation? And if need be, sleeve the block.

My 340 is .060 over. Seeing the wall thicknesses let the shop know it was fine for 3.31" stroke but a 4" crank was a no go. This kind of information allows you to make good choices based on you goals.

 

[Inertia]

Yep, we were going 060 over before sonic testing was readily avail prior mid 70s iirc.
But sonic check is done by everyone now .
I was starting to worry cuz I've had over a dozen running around out there , had to find that clip .

 

[diymirage]

If I had a 360, I wouldn't spend the money on a smaller 340 iether

Go with the bigger better block

 

[mygasser]

If I had a 360, I wouldn't spend the money on a smaller 340 iether

Go with the bigger better block

but a 340 block has bigger bores than a 360 so 'is' the bigger of the 2, not the other way around.

 

[QUINN FORBES]

They love 340s here in the south

They're pretty popular in the North too!
Keep keep keep!

 

[Ceedawg]

I’m looking for at least 3 more cores

 

[toolmanmike]

I’m looking for at least 3 more cores

Have you tried a Wanted thread?

 

[Mean416]

All 340s more than 30 over are garbage. I'm a metal recycler you can send them my way for a small fee.

 

[AJ/FormS]

but a 340 block has bigger bores than a 360 so 'is' the bigger of the 2, not the other way around.

but the 360 was born with a generous stroke, and is easily bored to 4.04
This not gonna go anywhere is it, lol
I still like DYs comment. the 3.58 stroke is very street friendly.

 

[harrisonm]

I would rather have a 340 that needed sleeves than a 360. I have NOTHING against 360s at ALL. They are great engines. There is just some sort of a mystic aura about them.

 

[AJ/FormS]

If I had a 360, I wouldn't spend the money on a smaller 340 iether

Go with the bigger better block

IDK anything about the 360 being a better block, but
I do know I'd rather have the 360, and I know exactly why.

 

[diymirage]

IDK anything about the 360 being a better block, but
I do know I'd rather have the 360, and I know exactly why.

I can think of 20 good reasons, right of the bat

 

[RustyRatRod]

That statement about the 77 and later blocks just isn't accurate. I had a 77 360 and it went .070 over for a 416 with plenty of meat left. It sonic tested THICK. I was surprised.

 

[str12-340]

If I had a 360, I wouldn't spend the money on a smaller 340 iether

yeah those 360s are much better, but I'll give you $20 for that useless 340 block anyway

 

[Kern Dog]

That statement about the 77 and later blocks just isn't accurate. I had a 77 360 and it went .070 over for a 416 with plenty of meat left. It sonic tested THICK. I was surprised.

The entire bullshit line about thin wall castings was pushed on us for too long. Larry Shepard should be kicked in the dick for repeating this blatant lie for all those years. Friggin idiot. 340s, 440s, all of them had plenty of cylinder wall thickness.

 

[Jeremiah (jd)]

Sonic tests don't lie. I think the cost of building an engine has driven people to check out the blocks more thoroughly prior to dropping 4k on parts and machine work to complete a short block. Generally I use .040 or less blocks for my performance builds. For instance,
I wouldn't build a 400 block over 4.380". Having had cylinders split at 4.375" on a 4.34" OE bore has made me cautious and skeptical. Most of the 340 blocks I have tested or seen the results from are similar to a 400 block - all over the place and not expected to be highly uniform. The main diff between the 340 and 400 block is about .030-.050" in measured cylinder wall thickness favoring the 400.

 

[gzig5]

I've had a hell of a time finding a shop around here that has a sonic tester or that have a honing plate for a SBM. I'm going to try and buy a tester off Amazon to check my three blocks before I take them in for machine work. Might have to make my own honing plate on the mill too. Not a big deal if I can trade it towards some of the machine work because I doubt I'll need it again.

 

[oldkimmer]

I've had a hell of a time finding a shop around here that has a sonic tester or that have a honing plate for a SBM. I'm going to try and buy a tester off Amazon to check my three blocks before I take them in for machine work. Might have to make my own honing plate on the mill too. Not a big deal if I can trade it towards some of the machine work because I doubt I'll need it again.

@pittsburghracer He bought a tester from Amazon I believe. Kim

 

[Inertia]

Remember, - boring .010 is only removing 5 thou of material, what's that, - 2 layers of alum foil ?

 

[jos51700]

****, when I was a kid in Central MO in the '90's, you couldn't find a 340, and couldn't afford it when you did.

God made the 340, and mankind created the cylinder sleeve to bless it and keep it holy when it got holey.

 

[duster 344]

There definitely is something about a 340. Some people say it has something to do with the bore to stroke ratio. I don’t know for sure. they only made them for so many years and there a rare and cool piece of history. Think everyone should be saved