hey if its ok, i have a question about what torque converter to use on the 340 I'm building. Will the stock 904 "hi-stall" 10 3/4 converter be fine or do i have to order something special?

I have installed a transgo TF2 shift kit. I installed the kit for the mildest settings it had as per the directions.

the cam shaft is a 262 / 272 duration
the rear end is 8 3/4

thanks so much for the help.

keni

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isaiah6:8
www.kenithomas.com

Does the 340 have a forged or cast crank?
What is the rear-end gear ratio?
If this is a street car, you need to keep the stall speed slightly lower then your typical highway RPM.
DD

Hey doug, thanks for your response
The 340 has a forged crank.
I do not know the gear ratio.
It was a slant six factory car w 8 3/4. rear end

But if stall should be slightly less than hwy rpm,
Which is generally about 2200-2500, , then the stock converter in the 904 will
be right at my hwy rpms. So am I looking for a "lower stall" option now?

That would confuse me as to the purpose of upgrading a converter at all

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isaiah6:8
www.kenithomas.com

It's a question of overall intended use vs heat buildup. (in short, how do you want to compromise?) The idea of a "hi-stall" converter is to allow the eng to rev closer to it's torque peak during initial off-the-line acceleration. But that added "slippage" generates more heat. If you drive mostly at a speed / rpm below your converter stall speed it will be "slipping" all the time & making LOTS of heat- damaging your trans. So either drive faster, or change your axle ratio to keep your cruising rpm's above your new stall speed- & add a good aux trans cooler.

Another option alltogether is to consider a later version trans that has a lock up converter (add a perf hi-stall L/U converter) - having your stall speed & good cruising rpm's.

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63 Valiant Wagon
225 - 4 bbl

Not to hi-jack the thread, just looking for info. I thought that all 340's (autos) were 727s and not 904s?

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50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

Your right,340s had 727s in them.Kenicb must be using what he has to work with.

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V8?? We don't need no stink'n V8!!

"So either drive faster, or change your axle ratio to keep your cruising rpm's above your new stall speed- & add a good aux trans cooler. "

Ha! I can always drive faster. I like that answer

I will stay w the stock converter. The 904 is my friend as is.
As with most upgrades, if I put in a hi-po part like a stall converter,
So much other stuff has to change as well. Thanks for the info, that helped

Keni

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isaiah6:8
www.kenithomas.com

if my memory is correct the 340 has two big counter weights on convertor

forged 340 convertors were Neutral balanced as with everything else. Cast 340 had that weird balancer. 360's and Magnums were Detroit balanced as a unit, no cross breading on those without doing some homework.

yes the 360 has a different harmonic balancer than the 340. Being externally balanced, the 360 has to be "balanced" both front and back.
Therefor, when using the stock 360 harmonic balancer you have two options to correctly connect your transmission. You can:

1) buy an after market B&M Flexplate that is specially balanced for a 360
This allows you to use the same neutral torque converter that was used with a 318 or a 340

or

2) if you use a stock 360 flexplate you will then have to install a specially balanced torque converter specific to the 360

thanks ya'll for the help on the small block question.

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isaiah6:8
www.kenithomas.com