Converter to flex plate issues

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