Converter to flex plate issues

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Dusterdude72

Dusterdude72

IN MOPAR MUSCLE MAGAZINE
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I had originally posted this in my build thread as an update but I figured I would post it in a new thread to catch more attention.


I would like to tell everyone I made some progress but it would be a lie .....KIND OF..... I decided I was going to put my tranny in.

I lubed the splines on the input of the trany and I lubed the torque converter shafts, got the converter to click into place no problem.

got the tranny under the car and up on the jack no problem.

Jacked it up into place and it damn near slid right onto the alignment pegs on the back of the block no problem.

Threaded the bell housing bolts in no problem at all.

mounted the cross member in no problem at all.

went soooo smooth (took like 10 minutes).

I got to thinking......man,this was to easy....I bet something stupid is about to happen LOL.

sure enough.

Went to put the torque converter bolts in and .....DON'T FIT!!!!

the torque converter all looks right....I put the starter in so I could see where the bendix lined up relitive to the ring gear on the converter and all that looks right.

What the problem is.......the bolt holes on my flex plate are about a half in away from the bolt holes on my converter.

so it looks like I have the wrong flex plate.

What I do not know is......is there a difference between a 727 flexplate and a 904? and maybe I have a 727 flex plate mounted to my block and it wont work with my 904 trans and converter?

or could something else be the problem?

ahhhhhhh gotta love it when the mopar gods toss a wrench in the cogs lol
 
Here is a quick diagram I made to kind of get the general idea of what the problem is...

The diameter of the flex plate is larger than the diameter of my torque converter which in turn is putting the bolt holes of the flex plate atleast a good half of an inch passed the bolt holes of my converter.

My converter is a TCI-141338 which is a TCI sizzler stall converter for a 904 torque flight.

the flex plate I BELIEVE is the original one to the engine which is a 1967 318 from a dodge coronet.

when I get the chance to remove the transmission I will measure the holes on the converter to check the measurements on it.

I was just seeing if maybe someone else already knew what flexplate I needed ahead of time? or what else they may think about the situation?

converter.jpg
 
After looking at your diagram, I'm pretty positive you know what your talking about, but you do realize the flex plate and TQ bolt together (index) only one way.
 
Yes I know they only bolt togeather one way.

My problem is,there is no possible way for them to bolt together lol.

the diameter of the flex plate is about an inch over all bigger than the diameter of the torque converter which in turn puts the bolt hole openings on the flex plate a good half of an inch passed the bolt hole openings on my torque converter.

only way you could get a bolt in it would be to put it through the holes on an EXTREME angle.....which is not correct.

the two holes should line right up and the bolt should be able to slip right into the one hole and thread right into the converter.
 
Oklacarcollecto said:
You do have the wrong flex plate.
Click to expand...

This is what I assumed also.

what my question is I guess...is,how many different flex plates are there? are they different between a 727 and a 904? different between a 318 and a 360?

I won't know exact measurements of my converter until I pull my trans back out but if by chance someone knows how to cross referance the part number of my converter (number at top of thread) and come up with the bolt hole measurements.....is there anyone that can tell me which flex plate I need and where I can get it?

I have looked at summit racing and there flex plates look like they are for a 904 and a 727 HOWEVER when I look up the part number through my local auto parts store (auto zone) they show two different flex plates with two different part numbers, one for a 727 and one for a 904.

so I am confused lol....I know what trans I have,what converter I have and what engine I have....I just don't know what plate I need lol
 
If your flex plate has the holes too far apart it is a 727. I would think if you have a 904 with a Mopar convertor that it would take the small flex plate.
 
Interchange shows 318 and 360 and most other V8 engines.


•With A904 Automatic Transmission 10 Inch Bolt Circle


•With 727 Automatic Transmission With 11-1/8 Inch Bolt Circle


You can use a Dorman - Flexplate (Rwd) Part Number: 04357 and it has both sets of holes.
 
Thanks for the info buddy.

Any one else care to chime in?

I also seen the 11 1/8" and 10" plates through searching

which I guess would be right considering I have "about" a half in difference in hole position.

Which would mean about a half in on each end ....which I am assuming is would probably total an overal difference in diameter from end to end as a 1 1/8" differance from my converter.

So I must have the 11 1/8" flex plate and a 10" converter.

I will know for sure when I drop my tranny back out and I can measure from hole to hole and I will make sure which bolt size I have also incase there is a difference in bolt hole size on a whatever flex plate I can get my hands on.

Good news is ....I have a 727 flex plate for sale it looks like LOL
 
I thought this thread was going to be the same problem I just encountered with bolting a flex plate to the convertor. All was well, convertor went into the trans nicely, the flex plate went onto the crank nicely, I knew I had to align the "hole" on the flex plate with the "V" on the convertor. I just didn't know that you couldn't see the "hole" once you had it all bolted together (and now in the car). So I turned and turned, and felt and felt, and looked and looked, but NO HOLE (I hate when that happens)! So I went trial and error, bolting one, then rotating, unbolting then bolting another, then rotating, Whew! Finally it was done after 2 1/2 hours and a pint of sweat!!
 
DusterDude72 said:
Thanks for the info buddy.

Any one else care to chime in?

I also seen the 11 1/8" and 10" plates through searching

which I guess would be right considering I have "about" a half in difference in hole position.

Which would mean about a half in on each end ....which I am assuming is would probably total an overal difference in diameter from end to end as a 1 1/8" differance from my converter.

So I must have the 11 1/8" flex plate and a 10" converter.

I will know for sure when I drop my tranny back out and I can measure from hole to hole and I will make sure which bolt size I have also incase there is a difference in bolt hole size on a whatever flex plate I can get my hands on.

Good news is ....I have a 727 flex plate for sale it looks like LOL
Click to expand...

You are welcome.

:angry7: I hate to admit it but I have been in this trap before.
 
Ok I see 1967 318. Correct ?

Is that a LA or Poly engine ?

Does your crank have 6 bolt holes or 8 bolt holes ?

Internally or externally balanced ?

10" or 11 1/8" Converter ?
 
Johnny Dart said:
What engine you running ? Year helps to.

Ok I see 1967 318. Correct ?

Is that a LA or Poly engine ?

Does your crank have 6 bolt holes or 8 bolt holes ?

Internally or externally balanced ?

10" or 11 1/8" Converter ?
Click to expand...

Not sure if you read everything or not.??

yes its a 67 318 as i stated above,it is a LA as Polys ended in 66,6 bolt,internal as it is a 318, and torque converter as I mention above i am not sure about until I can pull and measure unless someone can cross referance my part number above and get the measurements?
 
OK so I just went out in the garage.....without pulling the trans yet I couldnt get access to get a a good overall measurement of the converter or the flex plate BUT....I was able to measure from one bolt hole to the other (side to side not straight accross) on both the converter and the flex plate and this is what I came up with.

from side to side from one center bolt hole to another on the converter I was getting a distance of 7".

from side to side from one center bolt hole to another on the flex plate I was getting a distance of 7 3/4".

now when I took a piece of card board and laid these measurements out in the shape of a plus sign ( + ) the 7" (converter) measurements came out to an overall measurement of a 10" bolt pattern.

doing the same process but with the measurements from the flex plate...I cam out with 11 1/8".

and my bolt holes need to be for a 5/16" converter bolt.

so I need a 10" bolt pattern flex plate to match my 10" bolt patter converter with 5/16" holes by the looks of things.

I am confused with what plate I have as some places I see it shows 727 and 904 using the same plate and some of them show them using different plates and its confusing LOL.

Here is a diagram I made to " TRY" to explain the process of how I came up with these measurements.....kind of confusing though maybe.

converter diagram.jpg
 
Ok there is a 273 or slant six flexplate that is for early cars and has a smaller center hole then there is a small diameter and a large diameter flexplates. so from what I can tell you have the large diameter flexplate and need the small diameter one...but not the small one for early a's
 
first 318 I bought to build and replace a 6 cyl. came out of a Tradesman 200 work van. It came with a 727. A few years later when I decided to go back to a 904 the guy at the parts yard told me I will need the 904 flex plate also. If he hadn't mentioned it I would have been in the same situation.
 
sorry guys, I forgot to update the thread.....last week I ended up pulling the trans,measuring everything out and it turned out I had the 727 flex plate ( like I was pretty sure to begin with)....I called around to some place and finally found a local scrap yard and they had a STACK of 904 flex plates so I grabbed the nicest looking 10" bolt hole to bolt hole plate they had with 5/16" diameter bolt holes with a 6 bolt crank. picked it up for $10.00,also picked up a trans dipstick while I was there.

bolted everything back up and installed everything again and all went smoothly!

The 727 flex plate is now up for sale aswell as a BUNCH of other stuff in a forsale thread I have up if anyone wants to check the stuff out.

thanks for the help anyhow guys!
 
there were two different dia. flex plates. no idea why or what the application though. i know i have used 727 flexplates on 904 transmissions with no issues. nost i com across are the smaller dia.
 
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