Need internally balanced flex plate 340 / 904

[airwoofer]

The one I have for the 416 is actually a 360 plate that somebody welded back in the scoop area and rebalanced. It is not straight and I want a new SFI unit. Cannot find one specifically for the 340/416 with the 904. is the 727 plate the same for the 904? I have the 7/16-20 bolts.

Is the 10230 the right one and just use the 10" bolt circle?

http://www.jegs.com/p/B-M/B-M-Flexplates/748012/10002/-1

 

[Locomotion]

Yes. 340's never came with 904 from the factory so manufacturers don't usually list it as such. The B&M plates have all the holes you need to cover whatever converter you have.
The "solid 4-ear" flexplates would work also. But I don't like them because I've seen too many crack over the years.