Connecting Rods needed for try his crank

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Bronze Barracuda

Bronze Barracuda

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I have a 340 block heads and crank but no connecting rods came with it. The heads are factory 2.02 j heads. The block is either a 70 or 71 I believe all 3 parts were from the same complete 340. The casting numbers on the crank are 2532457 with a symbol that looks like a square circle with the letter f and a final number 4… So 2532457 F 4? See picture.
Anyhow I need to find some connecting rods that will go with this crank, also will need a harmonic balancer. So what year or casting numbers for con rods should I be looking for. Also what type of harmonic balancer should I be looking for?

PXL_20211202_043426717.jpg
 
Bronze Barracuda said:
I have a 340 block heads and crank but no connecting rods came with it. The heads are factory 2.02 j heads. The block is either a 70 or 71 I believe all 3 parts were from the same complete 340. The casting numbers on the crank are 2532457 with a symbol that looks like a square circle with the letter f and a final number 4… So 2532457 F 4? See picture.
Anyhow I need to find some connecting rods that will go with this crank, also will need a harmonic balancer. So what year or casting numbers for con rods should I be looking for. Also what type of harmonic balancer should I be looking for?

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You should get that crank cleaned up and checked before you put money into it.
What do the heads and block look like?
Do you know the current bore diameter?
 
That crank looks like it is ready for a 48 hour vinegar dunk and polish to clean it up.
 
my68barracuda said:
You should get that crank cleaned up and checked before you put money into it.
What do the heads and block look like?
Do you know the current bore diameter?
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Yes I am going to be sending all three parts to my local machine shop before I start my rebuild. As for the block as long as it is not cracked or compromised in anyway I will rebuild it even if it needs new sleeves. Also if heads are in good enough condition for a rebuild, I may still just go with some aftermarket aluminum heads, I will figure out the cost of rebuilding vs aluminum heads. If crank is no good what options do I have for a 340? Here's to hoping everything is decent enough to keep, and get f all of s good what con rods and type of balancer should I be looking for?
 
If that rust won't clean up on the journals They can still turn them .020 ths to clean them up, unless they are pitted beyond repair.
 
Bronze Barracuda said:
Yes! Hoping for a diamond in the rough! It had been sitting in an old garage since 1982
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PS is it possible to determine on my own if it is all good or do I need special equipment like a balancing machine, magna flux, etc. Or can I make a reasonable assumption with some decent micrometer? Before I waste money at the machine shop to find out it's junk?
 
To start with you can spray the crankshaft with WD-40 and scrub the crank journals with the red scotch brite pads to see if you can clean them up some.

Degrease It and then do an overnight Vinegar Dunk to kill the rust, polish it up with WD-40 And a scotch brite pad.
Then measure the journals with a micrometer and see if they are std size.

360s use the 645 press fit rods.
340s had the full floating rods. (Bronze bushing on the top)
 
You can get .030 under bearings.

If the journals are pitted deep it might be an ornament.
I'd let the shop give you the final verdict.
The insignia by the # is a forgery marking.
 
With new rods being so cheap, I wouldn't even bother trying to find some used rods of questionable condition that may need $$$ put into them. New rods, better steel, better bolts.
 
Any LA 318 or 340 balancer will work. If you find a 340 balancer make sure it does not have a weight on it for a cast crankshaft. It will say it on the front. You can not use a 360 balanced at all as they are all externally balanced. As for rods you can use any LA 318, 340 or 360. The early 273 and 318 rods will be lighter so I'd shy away from them although you can use them but balancing will cost a bit more. The 340 rods will be bushed on the small end but they other will work just fine if you like. You'll need to have the rotating balanced. Get the block and crankshaft checked first. If you decide to rebuild it give me a PM... I know I have two complete sets of 340 rods in my barn that are good that you can have for shipping cost. Be ready to spend so money, engines are expensive to rebuild anymore.
 
Hellrats said:
Any LA 318 or 340 balancer will work. If you find a 340 balancer make sure it does not have a weight on it for a cast crankshaft. It will say it on the front. You can not use a 360 balanced at all as they are all externally balanced. As for rods you can use any LA 318, 340 or 360. The early 273 and 318 rods will be lighter so I'd shy away from them although you can use them but balancing will cost a bit more. The 340 rods will be bushed on the small end but they other will work just fine if you like. You'll need to have the rotating balanced. Get the block and crankshaft checked first. If you decide to rebuild it give me a PM... I know I have two complete sets of 340 rods in my barn that are good that you can have for shipping cost. Be ready to spend so money, engines are expensive to rebuild anymore.
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Thanks definitely keeping you in mind
 
Possibly, I'm going to spend a little time on it first. Vinegar and mic it @ the least
 
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Well that will be the last post that will be deleted . I am off to another site . Thanks. All because I offered this man the parts he needs for the free just for price of machine work ready to use. If you can't give the **** away throw it away. Screw ya all.
 
360 Crank
Before and After Clean Up, have cleaned up some nasty looking cranks.
Vinegar dunks work good to break down the rust, need to be scrubbed up clean afterwards.

Final rise and scrub with distilled water after vinegar dunk, neutralize the vinegar. They will immediately Flash Rust.
So get to them with the WD-40 and scotch brite scuff pads for the final clean.
if storing more than a couple of weeks, coat the crank with some thin motor oil to protect it, and of course stand it on end.

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Bolting on a flex plate upside down with 2 crank bolts helps for working with the crank and keeps it from rolling off the table.
Makes a nice foot stand to for storage.

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Oldmanmopar said:
Well that will be the last post that will be deleted . I am off to another site . Thanks. All because I offered this man the parts he needs for the free just for price of machine work ready to use. If you can't give the **** away throw it away. Screw ya all.
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What the???? Free engine parts are awesome! No entiendo.
 
Oldmanmopar said:
Well that will be the last post that will be deleted . I am off to another site . Thanks. All because I offered this man the parts he needs for the free just for price of machine work ready to use. If you can't give the **** away throw it away. Screw ya all.
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I missed your post.
Don't let them get to you.
If it sounds like a deal..they move it to sale section or send you "please pm" deal. I dont know why it matters in a spontaneous situation like this..but it's their rules.
Besides..things are getting interesting here lately...watch..
 
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Bronze Barracuda said:
I have a 340 block heads and crank but no connecting rods came with it. The heads are factory 2.02 j heads. The block is either a 70 or 71 I believe all 3 parts were from the same complete 340. The casting numbers on the crank are 2532457 with a symbol that looks like a square circle with the letter f and a final number 4… So 2532457 F 4? See picture.
Anyhow I need to find some connecting rods that will go with this crank, also will need a harmonic balancer. So what year or casting numbers for con rods should I be looking for. Also what type of harmonic balancer should I be looking for?

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You’ll have to turn the rods down far enough that you should just go right to large journal small block Chevy and buy aftermarket chevy rods. You can find off the shelf pistons for the .927 pins.
 
Yeah I missed the thing from old man Mopar myself. But it makes sense to be able to speak about something that is in a direct info about the conversation at hand.
 
I offered this member rods for the price of resizing. A forged crank for the price of polishing and damper for price of cleaning. The poster/member asked for items . My post was removed and my offer was taken down. Then suspiciously I get emails not PM,s for the items in question. Then today I get a PM asking to renew my Gold. Are you Fu--en kidding me. Some of these moderators need to be gone. Another good site going to **** in my eyes. Did CRT reach here also.

Many years ago a member who died posted a lie . I called him out with proof and pictures. His story didn't hold water. Guess who was reprimanded. Its not what you know its who you know. Lived with the strike and the Mod. a$$ got away with it. WAFJ LOL. I'll use the $40 to buy some Pizza for the guys.
 
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