The little 340 plan is starting to come together

[dodge freak 2]

So took all my stuff to the first shop I visted a month ago. Place sure is dusty but guys are COOL, and Idid see short blocks waiting to get picked up sealed in plastic bags--so maybe they try to keep the important stuff clean.

First shop did a half butt job of cleaning the block they thought and they also want to punch it out .040, say .030 isn't enough.

They are thought the new SCAT cast cranks are pretty darn good--good enough for me.

So I thought why not get a new crank on 340 mains but a 3.58 stroke like the 360 has. However only Kieth Black makes a .080 over 360 piston and its forged-not hyper. Means $430 not $200 for a set. But wasn't too eager to run hypers. The crank is $300, heck just  to polish an old crank is $45.   

So haven't order nothing yet but right now I believe I going with SCAT 3.58 stroke cast crank and KB forged pistons which are 10.5 to 1 compression. So I get about a 372 CI motor for a little  cheaper than a more powerful-but weaker-408 motor..and the block will say 340    

[dodge freak 2]

UGH, those 4.080 pistons are for a 4 inch stroke--not 3.58!

Means the labor to notch the block will be a few hundred--means the walls should be check for thickness, means main studs are a good idea---means its getting too $$$$  

[challengermaniac]

340's are expensive to build and should only be done when you absolutely must have one and a 360 just won't work for you. 

ps: I just had to have the 340 as well!

[dodge freak 2]

Yeah but old 360 motors are hard to find it seems, those were thrown away long ago--before the good pistons cam out. The newer castings are weaker, my block is 1972, cast before cost cutting came along.

The main bearings are very large too.

Ain't my fault the dumb piston makers can not make .080 over 360 pistons, they do make .070 over-at least KB does

[dodge freak 2]

Seems like its going to be a 3.31 stroke after all. Found a 273 crank in Washington on the west coast. Around $160--shipping is $. Guy has been on ebay for 10 years and has a 100% rating over 300 and a 21 seller review for the last year. On forabodies only we hook up and went with pay pal---this is cool now of days. I remember the old check in the snail mail, lol.

So I just rev the piss out of it to make good power

[the_engineers]

You need a 4.080 bore piston with a 1.687 or so compression height.  Is it too late to mention this...http://www.summitracing.com/parts/UEM-1139-030/ ?  You'll have to bore the pin end of your rods IIRC.

Another option based on SB Chevy...http://www.summitracing.com/parts/UEM-1423-080/.  It'll put 'em .030 in the hole.

[dodge freak 2]

Hmm, but those pistons are cast and not sure about opening up the small end of my 38 year old rods. Guess they sell better pistons but new rods would be too much $

[the_engineers]

I thought from your 1st post that you don't want forged.   Just looked it up...340 piston pin is 0.984, so you'd have to bush the rods instead, standard practice on 340's.

[dodge freak 2]

I don't want hyper pistons if possible. Seems .040 over comes in hyper only--unless speed pro still makes their forged piston, Manici says he can not get them anymore.

This guy at my shop seems to know how to install the hyper right thou

[Moparal]

Here's 5 new  .030 pistons (forged)  clevite for 21 bucks each.   They are easy enough to find, I could find more, but you seem to be on a funny type picky budget. But if you look you will find   These are 68-71 type, right up your alley


http://cgi.ebay.com/ebaymotors/MOPAR-DODGE-DUSTER-DEMON-340-PISTONS-224-2565-030-_W0QQcmdZViewItemQQhashZitem3ef403e06dQQitemZ270381867117QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[the_engineers]

He is/was looking for 340 pistons that would let him run the longer 360 crank (3.58" vs. 3.31" stroke)  He'll need a piston that's at least an 1/8" shorter than stock.

[dodge freak 2]

Shop guy is saying it has to be .040 over--or .060 even--will not clean up at .030, he even ran the bore in and went .030 and its not enough--too much taper.

So .030 over pistons he will not use.

It looks like I be getting a late 273 forged crank with large torque converter register---guess the first ones had a smaller opening in back.

I hope it works out,