360 to 340

[cnrtybyathrt]

can you hook a 360 904 to a 340 seams to me i read somewhere you need to knock off weights or something aftermarket converter

 

[oldkimmer]

..........Yes u need to knock off the weights if there is any......forged cranks dont use any weights...........if u have a cast crank 340 they need a weighted damper and converter, or u can buy a B+M flexplate........kim......

 

[cnrtybyathrt]

thanks kim but i think i miss wrote i want to put a 360 904 on a 340 motor again sorry

 

[fishy68]

What year 340 do you have? Do you know if it's a cast or forged crank?

 

[cnrtybyathrt]

is this the flexplate i would needhttp://www.jegs.com/i/B%26amp%3BM/130/10239/10002/-1

 

[cnrtybyathrt]

i believe its a 71

 

[fishy68]

71 will be a forged crank unless someone has changed it. That being the case all you have to do is knock the big weight off the front of the 360 converter and run a stock flexplate like the 340 or 360 came with. Be careful when you knock if off that you don't rip the torque converter housing. A die grinder works good to grind the welds so it'll pop off easy.

 

[fishy68]

is this the flexplate i would needhttp://www.jegs.com/i/B%26amp%3BM/130/10239/10002/-1

No. That flexplate is for a 360. Use a stock flexplate or if you want an aftermarket flexplate get one for a internally balanced 340 (68 to 71)

 

[cnrtybyathrt]

thanks fishy i do know the crank has 6 bolts i just didnt want to bye i trany and converter and not being able to use it

 

[fishy68]

thanks fishy i do know the crank has 6 bolts i just didnt want to bye i trany and converter and not being able to use it

Your welcome. All stock cranks are 6 bolt flanges just so you know. You can tell a cast crank 340 from a forged crank 340 by looking at the harmonic balancer. If it's a forged crank it'll be perfectly round and won't say anything on it. Cast crank balancers say right on them "use on cast crank" or something of the sort. What this all comes down to is if it's a forged crank it's considered an internally balanced engine and does not require any weight on the converter or a special flexplate. If it's a cast crank engine it's an externally balanced engine and requires either a balance weight on the converter or a special flexplate similar to the one you looked at on JEGS. Should be no problem using a 904 as long as it's in good condition.

 

[cnrtybyathrt]

just went and look it appears to be round forge crank the tranny is rebuilt the man is suppose to find out what value body ect and new 3000 stall converter