Cast Crank 340's Flexplates for a 904 trans

[dodge freak 2]

Ok, do I got this straight.  318 cast crank motors are internally balanced but the 72-73 cast crank 340's are  externally balanced and would use a different B&M flex plate.

If so how do you use a cast crank 340 with a 904 trans (I know from the factory none came like it)

Just wondering in case I end up with a cast crank 340 and want to use it for awhile before getting a steel crank for it. 

[dodge freak 2]

Would the B&M cast crank 360  flex plate 10239 work?

http://www.summitracing.com/parts/BMM-10239/

[Chryco Psycho]

yes the balanced flex plate would fix the problem

[dodge freak 2]

Got off the phone with Manici Racing, he claim no the B&M 360 904 flex plate will not work and B&M no longer sells that plate. He said I need to buy a $55 Mopar converter weight kit that comes with a template showing where to weld the weights on the converter. Item # 4120241

ATI shows that they still sell one with a different part number than all the rest but also has a footnote saying the crank needs to be balanced with the flex plate attached.

Last thing I sure need right now is to install a different motor and the engine shakes and needs a different plate or weight on the converter, lol. 

[dodge freak 2]

I don't get why the 318 cast crank is internal but the 73 340's are external? The damper seems to be a problem as well, if old one is missing on a late 340

UGH, Manici just told me the 73 340 with a cast crank takes there own special damper that is twice as thick as the 318 and says for use with cast crank 340 only were the crank pulley goes on and over it. 

[tactransman]

http://www.summitracing.com/parts/BMM-10235/ This is the plate you need . 904 and 727 small bolt pattern is going to be the same bolt pattern.

[aduc73]

http://www.summitracing.com/parts/BMM-10235/ This is the plate you need . 904 and 727 small bolt pattern is going to be the same bolt pattern.

Dodgefreak 2, will that work? is this flexplate balancing good for 340/904 trans?

Im going to swap from 318 to 340 and keep the 904 (I dont want 727!!)Let us know hows it going!

[422STROKER]

I think I have one of those B+M flexplates somewhere.

Tom