Flex plate

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1972trucks

1972trucks

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I am restoring a 73 duster 340 all numbers sunroof car. It is an automatic. When I bought the car it was completely apart. Now the 340 is rebuilt and I am mating the trans to the motor. I have the torque convertor slid in place and have the flex plate mounted to the motor. My problem is I can only get 3 of the 4 holes to line up on the flex plate to convertor. The 4 hole is about a 1/2 of a hole off. I have tried all 4 holes but none will all line up. . . . help. Any ideas?
 
Turn the torque converter 90° and try again.

Keep trying they only go on one way, they only line up in one position, so the other 3 positions can be wrong.
 
1972trucks said:
I am restoring a 73 duster 340 all numbers sunroof car. It is an automatic. When I bought the car it was completely apart. Now the 340 is rebuilt and I am mating the trans to the motor. I have the torque convertor slid in place and have the flex plate mounted to the motor. My problem is I can only get 3 of the 4 holes to line up on the flex plate to convertor. The 4 hole is about a 1/2 of a hole off. I have tried all 4 holes but none will all line up. . . . help. Any ideas?
Click to expand...
Most Mopars run an "offset" hole in the flex plate to torque conveter bolt pattern.
Before I assemblied my 340 I marked the offset hole in the flex plate and the corresponding offset hole on the converter so they could be located after mating the engine to the transmission.
Now all you can do is hunt and peck your way through it until you find the combination.
 
The motor and tranny are on my hoist getting ready to go in the car so it would be easy to unbolt the tranny.
 
bcschief said:
I think he already did that, maybe a mismatch between the flex plate and the torque converter.
Click to expand...

Can the flex plate be backwards? The motor and tranny are on my hoist getting ready to go in the car so it would be easy to unbolt the tranny.
 
1972trucks said:
Can the flex plate be backwards? The motor and tranny are on my hoist getting ready to go in the car so it would be easy to unbolt the tranny.
Click to expand...

Maybe, but also torque converters made for later magnum engines did away with the offset bolt pattern. I would wait for someone with more knowledge than I to help, I just thought this might be your issue
 
Does your flex plate look like this?

Can't bolt them on backwards because of the offset crankshaft bolt pattern.

Is it an aftermarket flex plate? Should be a flex plate for a neutral balance 340 engine.

Screenshot_20220525-210050_Firefox.jpg
 
It's all numbers car. everything matches. does it matter how i put the flex plate on?
 
Compare how your flex plate is mounted to these in this picture.


Screenshot_20220525-212142_Gallery.jpg


These flex plates ^^^ are mounted wrong, but make good feet being bolted on upside down with only 2 bolts, for storing the crankshafts.
 
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I would remove the flex plate and try to line it up on the converter, if it does then mark the flex plate and converter and reassemble.
 
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