engine question

[dukeboy_318]

I read a tech question about a 340. The guy was putting a new converter in and noticed that the stock one had wieghts on it and the new one didnot.   The editor said to weld wieghts on to the new one in the exact same spots.  My question is does it need the wieghts and where can one find a new converter that already has the wieghts. I'm looking to put a 340 in my car backed to a sb 727  but i don't have the stock converter to get the wieghts.  What can i do to make sure that the engine is ballanced correctly?
Also what pistons would one reccomned to use in the 340. 
This car will primarily be used a a street machine with the occasional blast down the quarter mile so I want it to be durable and as bullet proff as possible. Thanks

[74340charger]

I was able to track one down from a guy localy, but in the event that I couldn't find one, Advanced auto parts had one that was a stock replacement. I also have a friend that has a fairbanks converter that has a stall and does really good.

[dukeboy_318]

 

[70charger_boy]

I believe, correct me if I was wrong, the weights were from the factory and they were balanced within 20 grams.  I would take it to a machine shop and get it balanced. I would pm member RD on this site because he's the expert

[andy74]

most decent tranny shops can add the corect weight for you,the only problem being if anything is different than stock(engine balance in particular)then you may need to consult your local speed shop for recomondations

[70charger_boy]

most decent tranny shops can add the corect weight for you,the only problem being if anything is different than stock(engine balance in particular)then you may need to consult your local speed shop for recomondations

[oldkimmer]

the only year 340 that needs the weights is for 1973 because it had an externally balanced crankshaft.......the damper will say ....use with 340 cast crank only , all other years used a forged crank and did not need the weights on the converter.......B+M sells a weighted flex plate for the 1973..340..........kim

[John_Kunkel]

340's built after April 12, 1972 have cast cranks and need the weighted converter.

The B&M #10235 flexplate allows the use of any neutral balanced converter.