Need Help with Torque Converter

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devildog

FABO Gold Member
FABO Gold Member
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Been a while since I have posted anything but I need help with a build problem. Long story short. I bought a partially assembled 340 block that already had a Mopar Performance forged crankshaft installed. The rear flange of the crank has an 8 bolt flange. I found a flex plate that would mate with the 8 hole crank but the diameter is smaller than the torque converter diameter that was already installed in the 727 trans. Now I'm looking for a non stall 11 inch with 10inch bolt circle, 24 spline and 130 tooth ring gear to mate it all together. Looked high and low and can't find anything out there. Called Precision because they listed one but they refuse to sell to me as they are a wholesale and you have to be a licensed transmission shop before they will talk to you. On top of that they said they had a $1000.00 core charge for a product that listed as re manufactured so it should go for a few hundred bucks everywhere else. Is there anyone out there that can help out with this or point me in the right direction? I appreciate any help I can get. This is all that is keeping me from finishing an engine (340) swap. Thanks
 
My mistake...flex plate with 8 holes is smaller diameter so that explains why I'm looking for the torque converter with those specs.
 
There are two bolt patterns for the factory converters . One for the 11.75 converters and one for the 10.75. Pattern for the 10.75 fits all the smaller aftermarket converters as well. All 340 cars used a 10.75 converter. You aren't trying to use a 11.75 converter behind a 340 are you ?
 
I'm retiring the 273 that was in the car for a 340. The 273 had the larger bolt pattern on the torque converter that was in it. they were all intended to mate with 6 bolt cranks. That's the problem. The only 8 hole flex plate was a smaller diameter and I can find no 8 hole flex plates out there other than the smaller diameter.
 
11 1/4 bolt circle on the torque converter and after market flex plate that was mounted in the 273. (6 bolt crank)
 
Can't find a part # on the torque converter. Just a stamped on date code of 072515.
 
I just can't make sense of what you have. Your engine is a 340 with an 8 bolt crank? If Yes, who made the crank?

Then are you installing this 340 in a 273 car with a 727 transmission that has a large bolt circle flex plate. large converter? What model is the car?
 
It could be an early 273 crankshaft maybe a 318-3 truck crankshaft? IDK there is a lot going on it that one.
 
If you are trying to find an 8 bolt crank flanged flex plate that will bolt to a large converter, it's not surprising you haven't been able to find one. Reason : There is no demand and almost no one would buy one . Solution : buy a converter that fits .
 
Yup, found the PRW flexplate yesterday and ordered from Summit. That will fit the torque converter (11.125 bolt circle) that was on the 273 and is being swapped. The 273 was numbers matching but had been heavily modified so I'm just going to put it on a cradle and save it. Think this will solve the whole problem. By the way, don't go to "Precision of New Hampton". They are wholesale only and will not sell torque converters to regular guys... have to be a certified transmission shop! Thanks for the help and advice.
 
DevilDog, PONH does sell to shops, that is true. All you need to do is talk with one of your local shops and have them get it. Sure, they will make a bit but not too much. And, they can help with some of the issues you have been dealing with. At least, the shops aorund here I have dealt with have been very helpful.
 
Appreciate all the help guys. The PRW flex plate is suppose to be here tomorrow (usually later in the day here) so I should know it is all going to work out by the end of Tuesday.
Thanks again to all.
 
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