My 340 block is a tree stump!!

[Challenger73318]

Had a machinist look over my 340 block to see what it needed to get cleaned up and be usable.  He said without the main caps it's basically as useful as a tree stump.  Anyone know where I can get a full set of main caps for a 340?  Should I even bother or pursue either a heavy 318 build or try to find a 360 to build?  The car is rarely ever going to be racing, so driveability and manners are important.
I'll shoot anyone that says "Hemi".  The bank o wife is already not so happy with me and the car.

*********Update
Talked to 2 other machinists and both recommended not using 318 caps on the 340.  This is puzzling because in the engine catalogs I have (PAW included), the 318 and 340 caps are listed as the same item. 

Goody:  Yes, I have the numbers 318 for my car.  I was hoping to avoid using it in case something grenaded and the block was damaged. 

*********Update

www.pro-gram.com
The good folks at Pro-Gram Engineering make a full set of 340 main caps for those interested.  #5 (rear main) is $400 odd dollars though.  Some major machine work there.

[GoodysGotaCuda]

Err how different are they from 318 main caps? stupid question, but i'm under the idea they have the same caps? i know they run the same crank, just the 340 was balanced different than a 318....

possibly 318 main caps and a align hone is all you need? and i think you said you had a 318, correct? 

i've only built one motor myself, second is on the engine stand. so im no guru, im sure someone here knows for a fact.

Edit: upon further research, looking in my sb mopar building book, they do atleast picture a 360 main bearing cap, and a 318/340 main bearing cap. And do state the 318s and 340s use the same bearing size, and the 360 does not..

[Green Drop Top]

Find another machinest, seriously!

There are lots of sources for main caps, look in any Mopar magazine and look into replacement high performance main caps, they are much better than anything the factory made and I would run them even if I had the originals. The block will likely need to be line bored or at least honed after they are installed, no big deal.

[moparnut]

Keep in mind if you dont get 340 main caps(correct me if I am wrong someone)you wont get the bolt taps for the windage tray

[moper]

you're wrong...lol  The windage tray bolts to the main bolts, not the caps. The hardware can still be gotten from MP. The caps you can buy aftermarket ones, or find a set. I dont know if the caps are the same for 318s. I'd think you could use them, but I'm not sure. 360s use a bigger main size, and no way will they work. All you need is caps, and bolts, and the block can be align bored/honed, and you're good to go. I have 4 at home left from a stroker project I built a customer last year. I dont have the 5th with the rear seal. But you're welcome to what I have. (I have al lthe bolts too)

[heminut]

The 318 caps will work fine, but I agree with the earlier post suggesting aftermarket caps. If you have to spend the bucks to have the block align honed (definately worth it on a 340) get the bulletproof caps.

[chrisII]

Err how different are they from 318 main caps? stupid question, but i'm under the idea they have the same caps? i know they run the same crank, just the 340 was balanced different than a 318....

..

good 340s (forged crank) were balanced the same as a 318. cast crank 340s for whatever reason were externaly balanced.this seems dumb since the cast 318 crank is a direct bolt in. if i hade a cast crank 340 i would chuck the crank and put in one from a 318  
   as for the 340 block in question: It is not JUNK. but will cost a pretty good chunk to save due to machene work involved with installing different caps. to some it may be worth doing, but it seems to me that your budget would be best served with a 360. especialy if you have the 340 heads to use. for a good driver i would put a good set of trw or speedpro (same thing) pistons and a mild cam into a 360 (probably go .030 over).i would keep it around 9.5:1 compreshon so gas doesnt become an issue. if you look around you can probably find a 360 core for around $100 anywhere in the usa if you look. thats less than you would spend on the new main caps. save the 340 block or sell it to somebody who really wants one.

[moper]

I need a block for my caps...lol

[Alaskan_TA]

The original caps were machined with the engine, so caps from another used engine are not likely to fit exactly right. Go with new ones for sure!

Barry

[moparnut]

you're wrong...lol  The windage tray bolts to the main bolts, not the caps. The hardware can still be gotten from MP. The caps you can buy aftermarket ones, or find a set. I dont know if the caps are the same for 318s. I'd think you could use them, but I'm not sure. 360s use a bigger main size, and no way will they work. All you need is caps, and bolts, and the block can be align bored/honed, and you're good to go. I have 4 at home left from a stroker project I built a customer last year. I dont have the 5th with the rear seal. But you're welcome to what I have. (I have al lthe bolts too)

Doh you are right,"even a broken clock is right twice a day"

[HemiOrange70]

The 318 cast cranks were not shot peened like the cast 340 cranks, so they are not as strong

[JimCuda]

I[m not sure why your machine shop guy didn't pull out a catalog and look up some replacement parts to make even more money. Any good machine shop would tell you that if you are missing your caps you can get new ones. If your missing your crank you can get a new one, cast or forged.

More importantly the main bearings would have to be fitted to your caps and machined to match the crank. A line bore/dial bore and or micrometer are some of the tools need to do this job right, something machine shop do all the time. I agree with the previous posts, I would consider a 2nd opinion.

Much like PAW, Summit has main caps for 340's as well.
http://store.summitracing.com/partdetail.asp?part=MIL%2D11300&N=700+4294908078+4294840100+115&autoview=sku

Mancini Racing also has something as well:
http://chucker54.stores.yahoo.net/mopen4bolcap.html

There is always ebay as well. What ever your choice, good luck with the build up and of course post some pics!

[bigblock4speedman]

What is the date on your 340 block?  You need to find a different machinest, seriously, as everyone said, just get more main caps and get it line bored for sure.

[Aussie Challenger]

If you want a sweet motor, the 318 crank will fit but is no where near as strong a crank apart from not being shot peened. After market or replacement main caps, your choice, consult the wife bank if you must, but, DEFINETLY get the block/caps line bored and honed otherwise your crank will bind leading to bearing and crank failure very early in the engines life. You may want to sell the 340 block, you will be able to purchase a 360 complete with change and later parts do fit plus you still have the 340 heads which are similar to the 360 ( excluding 6 pak motors ). The 360 responds well to modifications plus you cannot beat displacement.

[Chryco Psycho]

some 318s had steel cranks too & can be balanced to work for the 340