Torque Converter Issue

[Fixitmg]

So I am doing a magnum 5.9 swap in my 77 dually.
I was doing a dry fit on the floor and found out the original torque converter is too big to fit in the flexplate of the magnum! I have to keep that flexplate due to the crank sensor on the magnum engine. Everything I see on line they are supposed to just bolt up, but mine is too large to bolt up.
so the question is do what do I change to get them to match up.

And I am aware of the hole you need to reem out on the flexplate, but mine is simply too large to fit the flexplate without modifying it.
I thought i could get a different converter, but I don't know which one
any help would be helpful
Mike

 

[Dew359]

You might need to get the flexplate for a 5.9 or you can run and aftermarket https://www.summitracing.com/search/part-type/flexplates/product-line/pioneer-flexplates
I would think that would might be about to used a external balance one from any year

 

[58pwrwgn]

Maybe a larger torque converter was an option or it was swapped. A quick look at rockauto shows 11inch tq with a 10 bolt circle for yours as well as a 94. But when I look at a 74 d300 360 I see they offer a 12 inch tq with a 11.125 bolt circle. I assume you will have to find a different tq.