Is it possible to re-sleeve all 8 holes on a 340 LA-based block to a larger starting bore size. Say 4.10 to 4.25"? This would not be a race application, more like a lightweight/high torque street bruiser.

I'm not a machinist, nor do I fully understand the cooling properties of the LA engines, so sorry if this question is a little out there.

Thanks!

Good ??, i don't have the answer, but i would bet its not a good idea due to the 340 thin walls to begin with

Yes. Then the simplest and cheapest is to use a 318 block, as it will do the job just as well as another LA. The sleeved block could be weak in the deck between the cylinders, but with iron heads on it builds a solid structure, at least if you are not racing it. The sleeves will be wet, and could leak water, so you better use Bars Leak or similar to avoid problems.
An alterantive would be to concrete fill almost to top and bore out to your wanted size. Should be cheaper. Use a good cooler for motoroil, and increase the ring gap. Fun project!

If you do decide to do that make sure and use ONLY Ductile Iron sleeves

The real deal is this: After you have spent close to $800 on sleeving the block, the bottom end will still be the weak point. Get to the 600 hp mark and the block fails. The answer to both your questions is to use a race block.

R.

spend the money on the heads instead and you will have more performance

I see this magical 600 HP figure bandied about all the time yet no one has any pics of the carnage or proof that that is why the engine met it's demise. My new stroker should be in the 650-670 range with a stock block. If it splits in half I'll post pics.

Speed-O-Motive makes a 460 or 470 something small block using Darton .200 sleeves. You'll have to look it up as I can't get there from the work confuser.

OK up to a 471 CID, link added.

http://www.speedomotive.com/ps-615-74-speed-o-motive-uber-block-assembled-custom-short-block.aspx

i agree with dogdays. start with a good foundation. get a r3 race block. start out good, finish good. stay safe, seeya.

i had a stock block 340 with 620ish HP,,,cracked cylinder wall twice..now R3 block 7 years no problems,,,spend the money now not later...I'm just sayin

A guy here in town does this all the time to make a light weight race block. Uses flanged sleeves and interlocks them together. Supposedly makes a good combo. I have personally never done it.

PM me I can give you a name and phone number

Leon

Guitar Jones: That link you provided was awesome. Really impressed with how complete the whole engine package is.

I also agree with you on the HP ceiling being a non-issue.

Leon: thanks for the offer, would'nt mind seeing a photo of what this guy is doing.....

Hi grizzly,
The answer to your question is a definate "Yes !!!"
I am building a 457 cu in out of a 72' 340 motor.
It has been sleeved by Divorak ( think he is still in business in Waldo, Florida)
I will include a few pictures to show where i am at.
It is an Old project for me that I have still not finished as I have been running a big block 540 stroker and 8-71 BDS in a pro street/drag race dodge demon 340.
the 340 is out of this same car, but is not numbers matching to the car.
We figure it out like this...
4.200 bore size x 4.125 stroke crank or as the formula goes...
4.200 X 4.200 X 4.125 X 8 X .7854 = 457.19
I was told that I could go even bigger, but wanted to try this combo out first.
It has probe pistons that stick up .033 out of the hole.
W2 heads with 2.08 intakes and 5 angle valve job (30,35,45,60,70 )
Mopar Performance valves that are back cut/front cut w/ .372 stem.
Solid roller cam 622/624 and also split duration 258/264*
Heads where done by Dynamic racing engines in Tampa, Job # 253 & #254 ( not sure if he is still in business either?)
We have a holley strip dominator w2 intake with a adapter plate and a single 1050 dominator at this time.
Combustion chambers are 66 cc with the w2 heads and a fel pro .045 compostion head gasket.
Valve to piston clearence is .115 intake and only .028 exhaust ( so we need to flycut the exhaust side of the piston's a bit!)
Piston to head clearance is .135
rockers and cam are crane roller.
I have since bought a cat gear drive for it and need to do the machine work to install it ( drill and tap a hole in front of block)
Our block has been filled up to the freeze plugs with hard blok (had to make it/mix runny just to fill it and wait a long time for it to dry!!!)
Pistons have the ring lands moved down a bit for use with nitrous fogger set up.(just in case)
If we figure it right our pistons leave us at 12.2 to 1 compression ratio.
They are available in any combo such as a lower 9.to 1 ratio if we wanted to change ( we like to race!)
I would not be discouraged in the least bit to do it again with a block that had a cracked bore as was our case.
Not sure what kind of power it will make yet.
I dont dissagree with starting with the R3 block if you have the means, We did it with this one just to find out what we could build to be different.
Hope the pictures come thru!
Grant Eaton
386-561-1181.

Another Picture.
Grant Eaton 386-561-1181

Picture of the top of the cylinders
Grant Eaton 386-561-1181

I got a bunch of pics, but here is the last one for now.
Grant Eaton 386-561-1181

My dad has cracked a few 340 cylinder walls, NA stock stroke combos, IIRC one of the blocks had even been filled.

Thanks, Grant. The pictures look great.

That thing should make big power by the looks of your parts list. How soon do you think it will be up and running?