Stroking a 340

[340 Dart]

A couple of questions for you engine builders.

I am getting ready to put a 340 into my Duster and I just happen to have a good 360 crank that is doing nothing. I believe all I have to do is cut the journals down to 340 size and it's a direct bolt in. Right?

I know this probably wouldn't be worth it if I had to buy a crank, but I already have it so, why not?

What would the CID end up being and what are the pro's and con's of this?

 

[bobscuda67]

I have done this to my 340, .030 and 3.58 stroke and you have 373 cubic inches.
I had the mains cut down to 340 std.size. You will need new pistons with the correct comp. height. The down side is the high cost of the balancing. The mallory metal is really expensive. I have $500.00 in a cast crank, that includes a $80.00 core, which is fine for my street driven car that will never see anything over 6000 rpm.
You could have a lot more cubic inches for the same money in my opinon.

 

[Burntorange70]

I have done this to my 340, .030 and 3.58 stroke and you have 373 cubic inches.
I had the mains cut down to 340 std.size. You will need new pistons with the correct comp. height. The down side is the high cost of the balancing. The mallory metal is really expensive. I have $500.00 in a cast crank, that includes a $80.00 core, which is fine for my street driven car that will never see anything over 6000 rpm.
You could have a lot more cubic inches for the same money in my opinon.

Sounding like it is better to just get a 4.00 stroker kit if you have to get new pistons and on the + side you get 408 cid. for not a lot more money.

 

[GTXperience]

Sounding like it is better to just get a 4.00 stroker kit if you have to get new pistons and on the + side you get 408 cid. for not a lot more money.

I agree. After the machine work, you still have OEM used parts. Most stroker kits with Eagle 4" cast cranks and Eagle I-beam rods and good Ross/Diamond pistons are in the $1200-$1300 range. Steel crank/H-beam kits usually run approx. $500-$600 more. Note: Cast cranks on average cost more/use more mallory than steel cranks.

 

[340 Dart]

Hmmmmm.

The 340 is a 73 with a cast crank. I was assuming I could use the externally balanced B&M flexplate to balance it, but I didn't even think about new pistons.

 

[340sFastback]

You can buy the 3:58 stroker kit from Scat:

http://www.strokerkits.com/new_page_6.htm

Same price as the 4.00 stroke kit.

 

[345man]

keith black makes a hyper piston for the 360 crank for about 200-300 bucks

 

[340 Dart]

These are the pistons that are in there.


http://kb-silvolite.com/performance.php?action=details&P_id=135

Anyone know the calculations to see if they will work?

 

[bobscuda67]

That KB243 piston is made for a 340's 3.31 stroke crank.The pistons I used are the KB372's which are for the 3.58 stroke crank. They look like this.

 

[340 Dart]

Thanks Bob and everyone else that replied. That is pretty much a deal breaker for me.

I was hoping for a quick cheap performance upgrade before I actually put together a purpose built stroker. Looks like I'll run it like it is, as originally planned.8)

 

[345man]

let us know how it turns out, good luck

 

[mopar1962]

yall do know eagle makes a steel crank for 360 strokers right?

 

[340srule]

Good move wanting to wait on the stroker,if a good quality built one is'nt in the budget,just save and do it right,sure people build cheaper ones but what do they run and how long do they last..with the right stuff your 340 can get the job done too...i loved all my 340 builds,but none of them ever put the smile on my face the way my 416 does..