Balancing a 1973 340

[Cudatime]

Hello everyone, looking for some technical help!

My buddy and I are putting together a pretty much stock 1973 340 small block and I am confused on the whole balancing issue. There is so much info between the 340/360s when it comes to internal vs external and so on. Here is what I have:

Block # 2780930-340-S
Crank # 3462387
Balancer # 3751160
Rods # 2899495

I bought this engine tore down. The block, balancer, and crank are the original parts. The balancer does say "Use with cast crank 340" on it.

I realize this is a cast crank, externally balanced engine. It will have a 904 behind it. I did not get a flex plate with the engine. What do I need for a flex plate? What do I need for a torque convertor? Thanks!

 

 

[1 Wild R/T]

This flex plate allows you to use a zero balance convertor...

https://www.summitracing.com/parts/BMM-10235/ 

[Cudatime]

Thank you. I see it is listed for the 727 but has two different bolt patterns so it must also work for the 904?

[burdar]

There are separate part #s for a 360/904 and 360/727 so I assume they are different.  I don't see a 340/904 listed.

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

[7212Mopar]

My car has the original 904 and the original 318 was replaced with a 71 340. The 340 has a steel crank and internal balanced with matching dampener. There is no weight attached to the flex plate and converter. The flex plate appears to be a regular 340 flex plate with four fingers for bolting to the converter. It is not the round 360 type. I am not sure if there are differences between SB 904 and 727.

[Cudatime]

Thanks guys. I gave TCI Transmissions a call today and the service man knew exactly what I needed. I need a weighted flywheel and a neutral balanced torque convertor for my externally balanced 340. Thanks again.

[7212Mopar]

Flywheel for automatic? Is TCI talking about the ring gear for the Starter? I see some of their torque converter has the ring gear and some don't.

[Cudatime]

Sorry, I meant flex plate not flywheel.

[Chryco Psycho]

Depending which converter you use the 10 or 11 " use a different flexplate so you hve to pick the converter first and match the bolt pattern